why not get a limited slip while you're at it? better gear ratios plus posi-traction (without brake influence) is the ticket.
My condolences, Chip . Your car actually already has a 3.64, a ratio even shorter than the one I installed. BMW puts shorter final drive ratios in the autos. Ratio info here: http://www.bokchoys.com/differential/GearRatios.htm
LOL! I know you are not a fan of automatics. I also like manual, but in DC traffic there are times when the auto is nice. My ideal would be to have a 6sp coupe and a larger auto sedan or suv for the best of both worlds. Not to be a gear novice but, does the 3.64 mean that that is already a good ratio? How does that compare to the ratio on the 6sp version? Thanks!
Yes.. the ZHP 6spd has a 3.07, the auto has a 3.64. You can't directly compare because I believe the ratios in the transmission are different between the auto and the manual. Higher final drive ratio = higher RPM for a given speed = better acceleration = worse gas mileage = lower top speed (assuming your car is redline limited...all E46s are drag limited). My wife's S2000 has a 4.10 rear end ... it turns over 4500rpm at 70mph on the highway! (although it does redline at 9...).