that act doesnt mean shit... there's too many loopholes.
Well, it doesn't mean shit if it's a shitty tuning job that caused the problem, if the dealership can't prove the mods were directly responsible, they need to honor the warranty.
Only other loophole could be if you're financing through the dealership, and they slip a clause into your financing agreement that states you can't mod your new car, in which case, all they can do is deny you financing, they cannot deny you warranty coverage, even if they put a clause in the warranty agreement that says you will void the warranty if you use aftermarket parts on the new vehicle... Mag/Moss already states they cannot deny warranty service over aftermarket parts, and anything in a signed contract that is opposed to pre-established law is not applicable. The only way they could get you is if you paid $15 or less for the car in question, in which case, magusson-Moss is null and void.
Magnusson Moss may as well be the tuner scene's constitution. SEMA, the aftermarket shops and all those aftermarket companies would probably not exist if it weren't for this law.
Respect where it's due...