If your looking for raw cheap hp then go with the 6.4. The best programing thus far is on the SCT with Innovative tunes. They went 12.70's-12.80's in a stock truck with nothing but a tuner, no intake no exhaust all stock hardware (except dpf). I can say though I'm going to test drive a new ford 6.7 and a 2010 6.7 dodge back to back and see what I like. I want to go to a 6 spd hand shaker and no one offers it but dodge now. Ford is coming out with a new 6 spd auto that is supposed to be stronger than the 5r110. I have a 600hp tune in my truck and 38's and with 115,000 miles the converter is a little tired. I like the simplicity of working on the cummins being I do all my own engine work. Thats really my only complaint about the ford is that its hard to do engine work with out either pulling the cab or pulling the trans. The mega cab is nice too and the absence of up pipes to leak is also a plus (something that is common on the fords and gm's). How ever the new ford with its inverted heads gets rid of the up pipes so still cant make a choice till I drive them both.
