BMW and Dinan are two separate entities and there is absolutely no guarantee that a Dinan part will be warranty friendly with BMW. Dinan does nothing more than offer their assistance with the enforcement of the Magnuson–Moss Warranty Act in the case that your service advisor tries to pawn off your new intercooler upgrade as the reason for your rear speaker failure.
BMW NA as well as any other brand of car sold in the US can only void your warranty if the modification is directly related to the component failure. The
Magnuson–Moss Warranty Act was enacted to protect our rights to repair and modify our cars