OK we own a 5cyc MB and it is in a 2007 leisure travel van , just two of us, and we,ve spent over one month in the same spot camping ,fishing in arizona , yep were still married, ours is on the 3500 series chasis duel wheels ,gets just over 20 mpg ,seen 24mpg , why, diesel over gas, we like the quality of the engine, has 31k on it, just one minor problem. yep it cost a little more but IF i, ever sell it,ll come back. after all if the MB engine is good enough for FED X trucks , it,ll last me forever, my fed fed x guy says his truck has over 300k on it, same engine I have.and I love passing fivers going up the mountains.