Wife owned one from 2007 until she traded it in on new jeep in 2016 and drove it daily, only problem it had ever was a leaking cam cover that was easily fixed. Photo is from the day she traded it in.
I have an 18' 1500 Hemi and 3:92s, has long tubes, tune, and x-piped true duals sitting on 35s. Empty I average about 16mpg. I have a heavy 22' boat and when towing it I get about 9-10.
Just for clarification, going from a 4" piston to 5" piston is a 36% change not more than 50% as stated.
4" piston equals 12.56" in area 5" piston equals 19.63" in area, 12.56 divided by 19.63 equals .64 (minus the .64 from .100 to get the .36 (36%)