As other guys have said in there... . The transmission is the weak link. If you drive it hard, and plan on BOMBing the truck. Get it done right. I, like TractorFace, spoke with all 4 of the BIG trans companies out there. The guys at ALL of them are great. They all know how the transmission operates. Watch out for the smoke and mirrors, just get the facts. I see you are new around the TDR, Welcome. The transmission stuff can get quite heated around here. I'm not sure where your located. Try to find some local guys, save the cash, and ride in as many trucks as you can. I made my choice because of 4 reasons. Customer service is second to none, I was impressed how it operated, the price, and the Warranty is the best out there.
People will recommend the top things out there, Billet this and that, but not really know the reasons why. Sure you can break shafts, but why are you breaking them. Are you doing smokey burnouts and power braking the truck. Get the shafts..... You see what I'm saying. If your only doing 350hp, you will be fine with a good quality rebuild, an efficient converter and higher line pressures(Valve body).
My . 02
Any questions feel free to ask us. The only dumb question is one you didn't ask.
Josh