The propane is needed for the two lengths. The PSD gets the jump on the Cummins, but it is gone pretty quick without the propane. The weight is a killer. The Cummins is about two to three lenghts quicker if no propane is involved. I have a friend with a PSD with the chip and exhaust. . no propane. It is an auto and runs about door to door with the Cummins. It is a F250 CC 4X4 with 3. 73's. The auto is a big help in the acceleration department.
I like the PSD for traveling. It has more room. I can't stop anywhere without somebody asking me something about the truck or just commenting on it. My wife finds it annoying... I do sometimes. The Cummins rides a lot smoother. . but it should. It gets a lot better mileage 21-23 versus 14-16. The radio is better in the PSD. Both have the highend options. The build quality seems about the same. The PSD just turned 80K and has HONESTLY had no problems at all past the first week. I had to have the fuel pump replaced with 800 miles on it. NO CACKLE, NO TURBO BOLTS... nothing. The Cummins had a persistant oil leak which a competant dealer finally fixed. The clock spring broke before the recall notice as well... at the dealer pulling it out of the service bay... I waited while they replaced it. They are both really nice trucks... I wish Dodge would build a CREWCAB to narrow the differences are far as I am concerned. That 4 door option not being available is just downright STUPID!!!... CJ