I have one of these chips purchased off ebay for a 91 318is, the car runs much smoother and it does have more pep, I paid $54 shipped. It may not be as agressive as the Mark D, but it is well worth the price. My mileage has dropped about 2 mpg, but that could be due to my newer heavy foot. I was getting 29 now 27 on my loop. Takes less than an hour to install and is a great mod.
