Don't be afraid to mod your car!

According to the Magnuson-Moss Act of 1975, the dealership must prove the modification to your car caused the failure in order to void the warranty. For example, they can't deny coverage of a failed clutch by saying your aftermarket HID kit caused your clutch to fail, but they could claim your 8lb aftermarket flywheel contributed to it's early failure and rightfully void the warranty on your clutch. Also note that some dealership service departments will refuse to do warranty work on a car that's modded, but aren't actually voiding the warranty, they're just refusing to work on it. In cases such as that, it's best to just find another dealership that will agree to work on your car.