My 3-year lease is about up on a 2018 Ram 1500 3.6L I-6 gasoline engine and towing capacity of 7,300 lb. 3.55 axle. I feel it worked too hard pulling my camper so for my next lease I am considering the 3.0L Eco Diesel with 9.500 lb. towing capacity. However, the Ram salesman is pushing me to...