ORIGINAL: MoparGuy
I have been told that the M-M Act offers protection for the use of aftermarket REPLACEMENT parts. For example, if you replace your oil filter or air filter or any other part for that matter with a direct replacement from another manufacturer (Fram, K&N, etc), Chrysler cannot void your warranty because you didn't use a Mopar part. This would cover any part of the car, not just MRO replacement items or consumables.
The question here is when you MODIFY your engine with a different chip, Predator tune, CAI, etc are there then grounds to void the warranty if you have an issue. If you add CAI, headers, cat back, rechip, and modify the tstat and the engine blows up, is Chrysler legally bound to fix it under warranty? I've seen cases go both ways and I don't know the legal answer, if there is one. I'm going to check with my dealer and see what he says. CAI might not be an issue since Mopar sells one, exhaust probably not either. As for the rest, who knows.
It is a pretty grey area, but again they have to prove the replacement part caused the problem, if you installed a lower temp Tstat, they would have a very tough time proving that because your motor was running 10 - 15 degrees cooler, that caused the motor to blow.
I have also seen these go both ways with dealers, but if you know the law, and you know how your motor and what effects what, you can tell if your mod affected the problem.