I was actually told to run a stock tranny until with a triple plate torque converter until it blew and then get a heavy hauler built up by NADP. I talked to BD Diesel, Supreme Diesel, and NADP. All agreed any over the counter tranny build would not be the best bang for the buck.
By the time you buy there kit and then all the additional piecies that even a stage 5 does not include, it`s cheaper to buy one pre built and installed for about 6K. PPE stage 5 with input and output shafts already runs just over 4k, there are also a few plastic pieces inside they recomend upgrading but I can`t remember them right now. Did I mention the heavy hauler also comes with 1 year 25,000km warrenty...