Cattletrkr, tell your dad to do everything at once, he won't regret it. Espically if he pulls heavy, and may want to add even more power down the road, having a top notch transmission done all at once, he will be glad he did.
LAMiller, the flexplate on the 01's are a night and day difference from the 03's like mine. I spoke to a DTT rep and he knows what my upgrades are and he said I will be around the 500 hp mark and that I won't need a billet flexplate until I go to twin turbo's. Heck, my installer told me that my flexplate will be able to with stand 575 hp before I need a billet one. Don't think I'm heading in that direction for a while (twin turbo's) that is. IMHO, I think everyone who is thinking about a DTT transmission should call them directly and tell them what your plans are for your truck, and they will lead you in the right direction. One of the nicest companies I've dealt with. Easy to talk to, and they love to talk trucks.