Had another question bugging me. Do any of you guys actually know the horsepower gain going from a stock E88 to a stock E31? I'm getting my E31 in the mail here soon and was just curious. I'm not looking to hot rod, just gain back some horsepower that I'm losing from my elevation here(6,062 ft).
Best way to get back some elevation lost is a turbo. It depends if the e88 you have is an early or a late, if it is a late and you switch to a e31 you will gain some compression, but that is all you will gain.