It will void your warranty is the crappy dealers way of getting out of fixing your car at their expense under warrenty. If you read the act you are allowed to replace parts with ones that are better quality, now things like turbos and S/C's will generally hurt your warrenty, but if your tail light shorts and is inop it should be covered under warrenty as a S/C generally won't make a tail light short, but the broke rod won't be covered as the S/C and aggressive tune were probably part of the cause.
__________________ 05 - Zeon body kit, Saleen S/C, 3.6" pully, 90mm MAF, L/T Heders, Catted X-Pipe, Saleen Race Craft suspension, Axel brace, Pan hard bar. More to come this spring from my friends at PMP and Larry H.
65 - Street force coil over front suspension, Wilwood disk breaks at all 4 wheels, More construction in progress! More to come this spring from Simons Auto & Restoration! | 
New Car - Modifications and Factory Warranty? 
