If you are going aftermarket, I'd suggest the KW Street Comforts. They're not as common as the V series because they only allow for a modest drop of 35mm or less. The V series are not really performance oriented, but rather allow you to slam your car. It won't handle as well on spirited drives. The S/Cs have linear springs, just like OEM, that will be more comfortable and responsive than stock. Being height and damper adjustable, you get more than the BMW performance suspension for nearly the same price. Also, as mentioned above, I would change out the soft subframe bushings since they take away from any suspension tuning you attempt on this platform.
Last edited by nitehawk; 11-29-2012 at 08:56 PM.