Look for things that involve either the air intake or exhaust for more power or something that delivers more fuel but I doubt you want to get 5gpm on your truck. More expensive: exhaust system, supercharger (I think there is one for the 2.7L and 3.4L but not 2,4L), new intake, change gear ratios. Less expensive: switch to an electric fan, deckplate mod (some say it works some dont, it is definetly louder if that means anything), different air filter, tune-ups. There is probably a lot more stuff out there but avoid anything that "Adds 30 HP and up to 8 more mpg" that is inexpensive because usually they wont work like a throttle body spacer, fuel atomizer, magnets or $20 exhaust system. It all depnds on the budget.