I was wondering what mods I can get away with with out jeopardizing my both my GM Certified Warranty, along with my GM Personal Protection (Major Guard) Warranty (Click Here to see the coverage of MAJOR GUARD).
My question for this is.. what can I do to get even BETTER gas mileage out of my stock 2005 Grand Prix GT.. We picked it up less than a week ago, and the only thing I've done is added a K&N Drop in filter. Would an entire K&N air charger system be even better? What else can we do to improve our gas mileage further?