i am in the same stage as you with changing out my 5.4 for a cummins. i have built the truck the way i wanted and i love the body style but need more power for pulling my 29 foot gooseneck. which inter-cooler would be the best to use, the one from a 7.3 or a 6.0??? i'm also thinking of changing out the auto 4r100 for a six speed manual. which would be the best for that?