New member here just wanting to share some info with you all. Just removed a Gen II K&N 57i Induction Kit from my 2001 E46 325ci and fitted the original box back after some good advice from my local main dealer. This kit doesn't direct any cold air from the grills to the cone through the heat shield meaning not enough cold air was getting to it, thus not providing any power gain or mpg improvement. Nieve for buying the kit I hear you say - yes I agree! Was getting 28.5 average over many months with this kit. Now gone up to 30.1 mpg after normal driving for few days. The kit did give a great sound though, so if that's all your after then the kit is fine, if you want the rest of the gains you need some kind of adaptor kit I reckon - too tecnical for me I'm afraid! Hope someone found this useful!