the stock engine is not intended to break any world records, just "Cruise" around town. HOWEVER, I know MANY folks who have managed to increase the HP with K&N filters, some who have added the Borla exhausts, and others who have completely tricked-out theirs to a point where you wouldn't even recognize the daggum things. You can hit the
http://www.ptenthusiasts.com site to read about what's going on.