How much of a difference does it make between the 275hp and 300hp Cummings diesels? I'm looking at upgrading our gas coach to a Fleetwood with a 275hp but the newer coaches are using 300hp now and want to know if the 275 is lacking power that would push the manuafacturers into the larger engines? Is there that much difference between these two engines for a 34-38 ft coach?