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If you have feedback on one of my chips, please click the button above to tell me how you like it and I will add it here!

From an email received 18 Oct, 2014: 

Hi Mark,

First off, sorry for not getting back to you earlier.  As soon as i returned I had to clear out a backlog of work and didn´t have time to install the chip.

Secondly, thanks for taking the time to deal with me personally, it was much appreciated.

I finally got around to installing the chip on Friday.  What can I say but, BLOODY AMAZING!!!   I wasn´t expecting such a marked difference from stock. 

It´s so much easier to drive around town and the power delivery is much improved.  Even my wife commented on it.   I wish i had done this sooner.

I would still like to add just a little more oomph. Would you say it is worth adding lightweight flywheel and some s50 cams?


Albert   ( Toronto and Spain)
93 525i 5-speed with "413" DME. 

From an email received 15 Sept, 2014 - car is a 2003 540i auto :

Hi Mark, Please feel free to add this to your website – Kudos.
I was already happy with my 2003 540i, but being used to high performance vehicles I decided to have Mark design a flash for my 540.

The flash is used for 93 Octane and although I haven’t dyno tested the car, the seat of the pants response is immediate, crisp and linear

torque in the middle of the RPM band, right where it should be. This translates to a constant surge of power all the way to redline,

which –by the way, was raised an additional 500 at my request. I am very happy with the transformation of additional power all while

remaining civilized as a four door family car.

Mark is a consummate gentleman to deal with and can accommodate a tailored flash/chip at your request. You will not be disappointed.

From an email received 11 April, 2011: 

Can I say WOW!!! AWESOME!!!  I love it. Makes driving my BMW fun. This is my first BMW. And I am used to the American muscle cars (Mopar & Ford)

….. changing cams or carbs to make horsepower….getting my hands greasy. Not this time. Does not feel like a slug anymore. Light throttle and she goes.

  Great customer Service!! I had a technical problem and Mark called right back and helped me thru it. Thank you  Mark !! your Da Man!!
1992 525i 5-speed,  with "402" DME

Posted on the bimmernut forum  by DueyT on September 22, 2003 at 21:22:05:

Mark, installed the chip this weekend and is it ever nice! 

Whereas I would have described the car as "a bit lazy up to 4k, then snappy

above 4k" I would now call it "good and solid to 4k, and HOLD ON, VANOS is 

kicking in to redline!" I'd be really interested in seeing a dyno comparison but 

there's got to be a fair bit more  "oomph under the curve!"   As noted by others,

the idle is very smooth (but I still only start in 1st, maybe 2nd pointing downhill ;-)

and the engine seems to want to rev fairly easily. Whereas before

it seemed I had to push the gas pedal to make the car go, now it feels more like

moving the gas pedal forward lets the car do what it wants to do...i.e. rev and 

go! Hard to put into exact words, but it now feels like I'm holding the reigns of a 

horse that just wants to bolt. I'll try and get a range of subjective "test-points"

but the overall impression is that the chip now makes the car feel like it looks! 
Mark, if this is the beta-chip I'm sure the finished product will be worth every

penny you charge!



1995 540i/6 

Posted on the bimmernut forum  by Regsatx on August 12, 2003 at 21:35:15:


If you have an M30 engine, get this chip now!!!! If you don't, you're missing

out big time. 15 minutes to install. I let it idle 10 min and headed for the nearest

freeway ramp. Even with my Automatic tranny, it rocketed up that ramp on the

way to the fastest 85mph it's ever done. I didn't Want a ticket, but this was 

delightful performance. I had this incredible feeling that a lot more power was 

available above 3500 rpm range but city traffic not the venue for that kind of thing.

No flat spots, revs very smoothly and now I can feel a lot more torque.  Also, 

seems gas mileage is going to get better. I noticed the mpg indicator staying at 

much higher levels.  Went for another drive a couple hours later, it felt even stronger. 

Best moment of day: a new-looking, white Mercedes E-320 with what looked like

non-standard 18" wheels pulled into left lane about 10 car lengths behind me. I

moved to centre lane, let him get abreast and ahead just enough to see it was a

320, nailed it and went from 75mph to about 95 (only for about 20 seconds) leaving

him in the proverbial dust.

GET THIS CHIP IF YOU HAVE AN M30. I can only imagine what the EAT chip would do for a 5-speed! 

Reg in Texas

90 535i 202,000 mi. 

Posted on the ROADFLY E34 forum  by Chris on Aug 10, 2003 at 13:00:00:

I own an '89 535ia and until recently have been pleased with the power

it produces. Well I had been hearing all this talk about engine chips and

how much they improve power and torque, so I figure I should at least

look into what's available out there. I came across the E.A.T. chip and

 noticed that it seemed to be priced less than most others... Then i noticed

that people were raving about the benefits they were experiencing with

this chip. Not expecting too much, I decided to go ahead and order the

chip from   Mark is a great guy to deal with and 

made the whole experience that much better.

Anyway, the chip arrived sooner than promised and I put it in that very day.

It only took my 20 mins, and I am not by any means a mechanic. I started

the car and let it run for a minute or two to get the car used to the chip.

I took the car for a spin and wow... I almost had to get out of the car and 

make sure I was still driving the same car I have been for years. This little

chip is amazing... Hands down the best investment I have made since I 

bought the car. To anyone looking for a great performance gain in all aspects

get this chip. I had a better idle, better gas mileage, smoother pull through the 

revs and much better response. I am still amazed every time I get in the car. 


yet another satisfied customer: Chris Allen '89 535ia

Posted on the maXbimmer forum  by Sanjay on  July 9, 2002 at 3:53am :

I just got my chip done today, and wow!! what a difference.  I am kicking

myself for not doing this sooner. When I first had it installed by MarkD,

I could not feel a difference except that it was smoother. 

That was due to all of the traffic downtown. As soon as I got on the

Gardiner and let it out..... damn!! My head snapped back for the first time

in that car. I was so impressed I kept driving all night until now. Definitely

go see Mark for more bang for your buck. He was very helpful and 

explained it all for me so that I knew what he was doing and what to expect. 

Best mod I have ever done.

93 Mauritius Blue 320i 

Posted on the bimmernut forum  by Tre on  April 22, 2002 at 16:34:48:

I installed the E.A.T. Ultrachip in my 93 525ia (M50 w/ VANOS, DME 413) and want to share my evaluation.

First I want reveal what my expectations were: I only expected to "feel" any

power increases in the high end of the rpm range. Even then I thought any

increase would be peaky or short lived. Aside from this, I anticipated a smoother

running engine and perhaps a small improvement in gas mileage.

Now, I can enthusiastically say, WOW, was I wrong!

Right off the bat I noticed the car moved much easier with very little throttle.

Throttle response is much improved as well. ED mode: The car feels like it has 

more power everywhere, not just in the upper end. The 525ia is a notorious slug from idle to 2,000 rpms.

The increased torque from E.A.T. Ultrachip greatly improved this. 

Select the "sport" mode and the car is transformed. It accelerates much quicker and 

smoother from 3,400 to 6,300 rpms. Fuel mileage has improved by more than

1 MPG to date. I truly expect this to increase even further do the fact that I have

been "experimenting" with the performance gains of the E.A.T. Ultrachip all too frequently.

Obviously, I recommend the E.A.T. Ultrachip. Installation was quick and easy.

It took me less than 30 minutes and I performed the chip swap at work,

in the parking lot. This is an upgrade that definitely registers on the seat-of-your-pants

dyno. If I had to broadly summarize in one sentence how my car feels with the Ultrachip,

I would say, "my car feels about 750 pounds lighter".

Posted on the bimmernut forum  by Themozzer on April 02, 2002 at 20:17:37:

I want to take a moment to explain the very pleasant

experience I had with Mark D'Sylva's E.A.T. chip.

First off, Mark explained everything a "novice with money" would want 

to know. Mark, told me what rev limiter is, and he helped me identify my

 DME (computer). I have a 1991 525i M50, and the computer was a 405. 

Mark custom programmed the chip for me and shipped it quickly.

I got the chip and I put it in, and holy crap... Did my lower gears take off.

 My 525i always had poor acceleration at lower gears and RPM. It was 

so bad that I felt like I was pulling my house behind me! My top-end speeds

 and acceleration was fine.

Now, with the chip, I can take out rice grinders with my 4000 Lbs car!

What a pleasant experience.

Also something weird; much better mileage. I used to average 25.5 MPG,

now I am getting 27. Same gas, same paths of travel. I don't understand 

how, but I don't care! Every fool who has not upgraded their chip, upgrade

 now. Mark will work with you to ensure that you are getting the appropriate

chip and such. What is $199 anyway, you spent that much on Easter candy for your kids.


Awesome! Outrageous!

It is totally beyond belief how such a seemingly tiny little thing such 

as this chip could make such a HUGE difference. 

This is more than a 'performance chip,' it's a new way of life! 1st gear, 

2nd, 3rd, what does it matter? This 2 ton behemoth flat flies like there is

 no tomorrow! There's plenty of increased low end torque. The factory 

flattened midrange is totally gone, and oh the sound. The sweet sound 

of effortless power. No ping, none. I'm impressed and almost feel guilty 

at the small price paid for such a large gain. Kudos to Mark. Now on to

 some wider rear wheels!

John Niskey
McCrea Nissan
Eureka, Ca.                           

Early '91 M5                          (feedback received 28 March 2002)

I have used the E36-413R chip since August 1999 in my 325is with VANOS.

This chip has amazing throttle response and top end power.  I have tried

other brands, this chip out did them all.  I own a repair shop in Toronto

specializing in BMW.  This is the chip we sell. 


re: the 90' M5 D'Sylva : 

Results so far... 60 miles covered (give me a chance, its only been

installed for a couple of hours!) ...initially...different. Then... smoother..

 Much smoother... even changing down seems to be easier as it revs 

with ease.. And climbs all the  way up to the top (somewhere?) in a 

very progressive manner.. Lots more pull low down. and the exhaust 

noise seems a little calmer for a few more hundred revs... then all hell 

breaks loose.. And the bad driver in me even managed to scrape a wheel,

 but no visible damage..So far.. very impressed, can't wait until tomorrow 

when I can drive in daylight, I'll have a greater chance of missing the kerbs!

Steve Maher (UK)

If you do not have one, buy one. I am VERY satisfied with this tuning.

Noticeable torque increase over Shark's chip, better mileage during

highway cruises at 80+, etc. Get one while you can save a buck or two.

Give them as Christmas presents. Help Mark pay his wife's charge card bills.

Put one in your PC and see if it will outperform a Mac.   OK, I'll stop.

--  brad barber

peace. love. track.

Your chip was installed yesterday 10/3.  It is kick butt.   The

chip removed was a Dinan.  There is a very noticable difference in the 2000+

range. In 4th it is even more pronounced.  I am extremely pleased with it.

I hope somebody else has a dinan in their m5 to see if their results are

similar to mine. Thanks again.

1991 m5 black & bad.

Review of the E34 S38B36 M5 chip:
I was fortunate enough to get the newest version of Mark's chip in the 

mail  last Monday evening.  I have been using it since Thursday.

 It is fabulous! My observations from switching from the Dinan chip to Mark's chip are as follows:

 * Power comes on strong and smooth. Especially in the  typical "Dinan hole" of 1800 - 2800 rpms.
 I was slightly annoyed in traffic this morning and decided to give a protest "chirp" of the tires. I spun the

 wheels pretty good (back end slid!) I had power the minute I let off the clutch.

 * Rev limiter is back. I very carefully tried to "bounce" the limiter and it came on right where


 * I have no pinging issues. We have 93 octane here in NC. Felt great with the A/C on going up a decent hill.

 * Idle is smoother, but exhaust still sounds great.   For those of you who have ordered the chip, you in for

 a pleasant experience. Those that are curious and have  questions, feel free to ask.

 -Ben Antanaitis

 aka benster

Greetings all,

 I went down to Bullet today to pick up my new tire (blow last weekend

 on the 5/55 interchange down here in OC, CA.) and who should I see, but

 Jordan.  He asked if I had installed Mark's chip yet, and I sheepishly

 replied that it was still sitting in my garage.  As an aside, I saw Dave's

 M5 there w/ his VERY fat tires -- nice! :)

 So when I got home, I was inspired (or shamed?):

 First impressions of the chip (only took it around the block..)

 1) Idle definitely seems smoother.

 2) Throttle response seemed better too.

 3) Not sure about the power -- I don't know if it was me or

 the chip that seemed more eager to move around cars.

 In any case, overall very impressive.  Perhaps at some point I'll  get a dyno done.


 - Ben M

I just installed your chip last weekend and haven't had the chance to really

wring it out yet.  Initial impressions are that the power delivery is

smoother across the rpm band than my most recent JC chip and the idle is

marginally smoother.  Power down low is somewhat better, however, I may not

see the increase here as much as others since I have the Dinan Cam Gears

installed which also serve to increase low end torque.


My '91 M5, quite clean of carbon engine responded well to Marks' chip. 

The telling difference over the Dinan chip in my car was the fact that all of a 

sudden, on full throttle, my wheels are breaking loose on initial Acceleration and again

at around 6K rpm on up ... extremely pleasing to the senses. 

Objective assessment; no seat of the pants difference at low rpm, 

significantly increased throttle response, very noticeable increase in power 

above 4-5k rpm. No flat spots and no pinging that I've noticed yet. 

Mark, nice job!

BMWenthus (Bruno)
'91 M5      w/Mark D'Sylva chip

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Last modified: 22 Oct. 2014