ahh, as far as i know, there is no bmw the the desination "k". but i mostly know about e30's. but the euro 320i may be an e30 and not an e21. if i rember right there were always a few models in europe that were not imported to america. so that may be a model of e30 that we never got.

IMO for strait line performance the only worth while e30's are the 325i. the "is" has suspention goodies to help with cornering but the motor is identical to the "i" so the sport model wouldnt realy be to your bennifit in strait line performance. the "ic" means convertable, and its to heavy... "iX" is all wheel drive and the drivetrain is to weak to handle any real power. the Eta (or 325e) is..... uhh, i hesitate to say this but i think its kinda worthless... it has a low rev limit, it has relitivly low horsepower (124 -128 depending on the year) but it does have a decent amount of torque. with a bit of modification to the valvetrain and a cam swap, you can make those motors put down a decent amount of power. but as they sit stock.... there not all that fast. the M3 is a pritty good car for strait line also, but personaly i think the M3 is overrated and its far to expensive. its mostly a road course track car right from the factory.

if your looking to autocross, the 91 318is is lighter than a 325, it has better weight distribrution, and decent power for autocrossing. (120hp~ something i think?)

i have turbocharged my 325i with a garret t3 t3 .63 .60 and at the dino on nine pounds of boost i increased my wheel horse power by 80 wheel horse. the m20b25 (325i/is) motor is very strong. i have over 167,000 miles on the stock bottom end and the cylnders dont show any signs of liping. i know several other people boosting 12.5 to 14psi on the stock bottom end with no problems.

so, stock an "i" is not all that fast, but they can be made to be pritty tough for not to much money.