The existence of aftermarket parts does not automatically void your warranty. They must prove that the failure of a part is caused by or related to the aftermarket part to deny you warranty. Of course, you may have to get a lawyer involved at that point if they try to screw you.
Audi R8 V10, 6MT, Ibis White
BMW i3 REx Mega, Laurel Grey
[Retired] BMW Z4 sDrive35i, BMW 335i Coupe