Youve got nothing to worry about with diesels. Diesel motors run a hell of a lot longer than gas engines do. Take the cummings motor. six cylinder 5.7 inline turbo. They are designed off semi engines with the same concepts. My buddy has a 96 with 160 on her and hes just about to put a racing tranny in it for the power he is pushing (quite modified). And no matter if you are towing or not they still get 20 mpg. Its crazy why I even drive a gas truck.... Ive been looking for a cummings or powerstroke for awhile myself infact