[myfirstbmw335i]

If this is a repost, sorry. These links explain pretty clearly actions needed to prevent the manufacturer (BMW in this case) from voiding your warranty based solely on aftermarket performance parts being installed on your car.

Basically, the manufacturer must prove that the performance part is the actual cause of the malfunction and cannot void the warranty just because the parts are installed.

One link explains the law and the other offers suggestions on how to procede if your local dealer is being a jerk about it....

happy reading and hope this is a helpful post....

http://www.turnermotorsport.com/html...nty_info.shtml

http://www.enjoythedrive.com/content...teria=Magnuson