I'll add this too - 400 hp is a lot, and I mean a LOT of power. It isn't unachievable, not at all, but wow, that's more power than even I will ever need. I just got done doing the 'standard' upgrades to my rig - PDR HX-35, PDR fuel pin, injectors (PODs), 16cm collar, our own 4" Intake and exhaust, and of course cranked up the pump including the 366 '3400 rpm' spring, and I slapped down a very serious and stable 252 hp and 561 tq at the tires at 6800 ft altitude. I doubled my power. The truck woke up so much that I am pretty certain I will never need any more than that. Actually the power is a little higher now as I added the PDR fuel pin after the dyno run so I'm maybe up to 270 hp and 630 tq - that's essentially the same as the new 2008 rigs are making, and for $30,000 less.
You can get 400 hp, but the question is will you really need it? About the only upgrade I can forsee for my rig is a Snow water/meth kit, which is good for between 50-100 hp depending on the spray, but I want it for when I am towing heavy heading up the Rockies. The water/meth kits are great for cooling the exhaust and adding power very safely - a nice perk when you really need it. I won't want it for the extra power - just for the cooling so I can stay in the throttle and not melt pistons.
- M2