Aftermarket potential is an interesting topic, because this is where the debate gets very heated. Take a Chevy 6.0L, add a $3,750 supercharger, $400 after-cat exhaust, $550 headers, and a $350 programmer and in theory you could make 500hp and 525lb-ft of torque. This $5,050 investment (minus installation) is still $260 less than the Duramax diesel option. Spend the $5,050 on diesel aftermarket parts and in theory you could have a 700+hp and 1100+lb-ft stump-pulling monster on your hands. However, that is $10,100 more than the initial gas-powered stock investment and ten grand is a huge chunk for anyone.
Towing is the final piece of the debate puzzle and here there is a definitive winner: diesels. Because of the crude characteristics of diesels, super-high compression engines are used to maximize power and with most diesels red-lining at or around 3,100 rpm, low-end torque is unbelievable. Huge torque plus low rpm equals towing that is unmatched by any gas-powered truck. With the internals turning at such low numbers, diesels typically last two to three times longer than equally worked gas engines. Towing can really take a toll on gas engines and transmissions because down-shifting and high-revs are part of the workhorse equation.
Sure, people are saying diesel is the wave of the future and crude oil is depleting too quickly for demand, but right now, the debate still rages in the truck world. With the dust settling and all bets off, concluding this debate is easy. If you tow more times than not, go ahead and fork over the additional five grand and get your money's worth. If, however, towing is not necessary Monday through Friday, a gas-powered truck will easily suffice and keep some greenbacks in your pocket.