[mpartric]

this is a neophyte question, but I don't see it answered specifically on this forum. It is frequently alluded to by other members that "this is not necessarily the options that I have on my car, etc..." and I assume this is to protect us from having the warranty voided by sadistic service advisors. I assume changing the ECU, turbo, intake manifold, etc would void the warranty. I couldn't care less about voiding the muffler warranty for obvious reasons. What about CAI? When I had my Mini they had no problem at the dealer letting me reflash the ECU and switch out the intake, however I get the feeling that my current BMW dealer is none-too-happy about this scenario. I would like to put a CAI on my car, but haven't done so for the aforementioned reasons. What exactly is the legality of replacing a CAI in particular? Isn't there some law, Magnusson or something to that effect, that prevents the dealers from rejecting the warranty for unrelated upgrades?

[darkphantom]

This has been discussed many times, just :

To answer your question, your warranty will only be voided if the problem found can be linked,traced back to your modification by any means.

A suspension mod will not void the transmission warranty, unless they somehow found out that the suspension was done incorrectly, causing some variances in the driving which placed more stress on the transmission somehow, in turn your transmission would be out of warranty in addition to your suspension...

[Driver72]

Your best bet and to avoid ANY hassles, just call your local BMW dealer and ask the Lead Service Advisor.
Let him know you want to put a CAI on your car to allow it to breathe better.
Ask him if there is any warranty issues in doing so.

CAI's are often sold by dealers and manufacturers "performance divisions" so there should be no issue, but better safe than sorry, so ask first.
Call 2-3 dealers in your area as well to get a consensus.