My .02, check it out very closely. I had a buddy fly down south to purchase a "well known" racing/dyno 3rd gen from supposedly well known "performance guy". The truck was to have made over 1100hp on spray. After purchasing it and driving it back, it has been a disappointment to say the least. At our Fall Brawl, it fell well short on the dyno, and left about 2 quarts of oil on the dyno floor. There was a bunch of shoddy workmanship on that truck IMO, and I felt bad for my buddy who was looking to crack the 1000hp club. It needed a lot of work, and wasn't what he bargained for. The old too good to be true deal. Choose wisely.
I have to admit, the more stout bottom end is appealing, but overall, sometimes you don't know what you've got until it's gone. That's why I'm keeping mine. It's paid for now, and soon I can start saving for some upgrades, instead of buying a Cummins, and starting all over. I'm halfway there now.
Good luck with whatever decision you make.