by law, as long as you dont open the engine case and modify anything internal and all modifications are bolt on items, the manufacturer cannot void your warrantee. They can, however, void the warrantee if the modification interfered with the normal operation of the engine. An example would be a supercharger kit. If the kit was installed professionally and the motor had a transmission problem, they could not void the warrantee due to the supercharger. But if you decided to install a high boost pulley on the engine and the supercharger caused you to blow a hole in a piston, forget about any warrantees.
A K&N air filter, for instance, cannot void a warrantee
Yep! But as a precaution, if it's a new car and under warranty, I'll pay a little extra to let the dealer's guys do it, for electronic ad-ons that involve cutting wires... E.G....add-on Remote Start, different radio, etc, from a stereo shop! Simple stuff, like extra Fog lamps, Running boards, ........no biggie!
The Federal Magnuson-Moss Law (think I spelled it right?) gives you the right to do this. But you could have an issue if battery drain, for instance occurs, and you had an outside shop do electrical work involving major wire surgery. So just beware. Yes K&N drop in replacement filters are fine, whenever they become available?
Used cars, out of warranty...........go to your local alarm/specialty shop!! :thumb: