"One of the most popular mods we install are new front grilles and air intakes," says Burlingame. "If you've ever gone jogging, you know how important getting enough oxygen is, and it's just as important to your truck. Switching to a performance air intake and exhaust system keeps any diesel engine well supplied with oxygen and functioning at peak capacity across a wider range of speeds."

A new grille also gives a truck new style, he says. "Going from factory standard chrome to matte black changes the whole look of your truck and sets it apart in a crowd." As truck sales have increased, being able to pick out your truck in a parking lot full of GMC/Chevy Duramax, Ford Powerstroke and Dodge Cummins has become more of a challenge, but new custom trim puts your unique stamp on your truck, he adds.

"Commercial diesel trucks work hard, and after-market kits can help them do more," says Burlingame. "Replacing the back-mounted ball hitch with a more centrally mounted gooseneck or fifth wheel hitch shifts the center of gravity of anything you're hauling forward, making it easier to pull big loads. You'll also notice better handling and maneuverability, so if you're hauling long or bulky loads such as multi-horse trailers, upgrade your hitch first."

Under-the-hood modifications can also increase overall performance, but it's best to let a diesel engine repair and maintenance specialist handle these jobs. "You can wring more performance out of your engine when you override the factory settings on your electronic control module. Think of it like over-clocking your computer. Not every repair center's able to do this kind of work, though, and changing your ECM settings isn't a home project," says Burlingame. "When in doubt, check with a repair center that specializes in diesel engines."