Ha thats funny Cummins detune the ISB for P/U truck use the horsepower limits of the 5.9 is pushing it now for maximum reliability. Cummins sure has you brainwashed the ISB started out a 160hp the marine version at 370hp isn't constant duty thats pleasure craft rating. If the Cummins ran at that power all day and everyday it would last less than a year myself I don't believe that the ISB is what Cummins claims it tobe. Its a crock of **** that Cummins claims the ISB is a medium duty truck engine you put that in a 5 ton truck is barely adequate.
As for buying a diesel its the only way togo if you are travel alot or your using the truck for serious work for guys like me that are in the construction industry diesel fuel is alot cheaper to buy and more cost effective.
I would go and test drive a some diesel P/Us before you consider ordering one you may not like the way it feels or the noise a diesel produces. The other thing is is diesel fuel redilly aviailable in your area I have read that not many gas stations have diesel pumps in parts of the states.
Here in Canada diesel is everywhere most of the trucks are diesel powered and its 10 cents cheaper per litre.
So go try out a PSD Ford Chevy Dmax or Dodge Crummins and see which one you will like best I know Chrysler dealers will damn near suck your **** to make a sale.