Hey i noticed that most intake systems mainly the air filter are circular cylinder style. today i took the air filter out .. nd it was like a box. i want to add tiny bit more horses into this car, i no you can probly get around 5hp more with a mass air flow airfilter. but the ones ive seen are circular/cylinder style. i was wondering if i could put those into my car???? also adding a cool air intake increases the deep/agressive tone of the car right? im sorry for sounding stupid but im jus geting to know cars, i fell in love with bmws after the driving experience. its soo fun to drive, your like.. ONE WITH THE ROAD.. ive driven lexus's and other cars, but BMWs.. the driving experience is amazing.

anyone got ne advice?

I think your car has the combined paper & foam air filter. Replacing it with one meant for a E36 or E46 M3 (all paper) will gain as much as a CAI, will only cost $16-20, and won't have the disadvantages of a CAI (contamination of the MAF and possible water ingestion).