Do a search for CAI, then you can spend the next two days reading the debates. The general consensus is:
A. None have ever been PROVEN (dyno before and after) to produce any HP gain over the stock set-up.
B. You must chose either the:
1. Short under hood type (Not a true COLD Air Intake, since it draws hot air in) OR
2. The long true CAI which draws air down near the road in front of the wheel, and puts the car at risk for hydro-lock destruction of the engine.
C. Any oil soaked air filter could contaminate and ruin the MAF.
D. To have any performance gain you would need to improve the intake path (CAI, throttle body) the exhaust system (more air in, more air out) and change the engine management system to take advantage of the improved breathing.
E. Most who have them just like the sound. Psychological performance boost.
chiefwej 2003 540i ///m-tech 6-speed
Black Sapphire Metallic w/gray
Last edited by chiefwej; 04-29-2010 at 01:17 PM.