I'm running a 4R100 with a PCS controller behind my 616hp Common Rail, and I can tell you that it's a great combination. Eric Schertz at Dynotech Performance in Long Island NY built my trans and so far it's been holding the power great. No billet parts other than an input shaft. He machined some parts to make room for additional clutches etc..etc.. just left out the pixie dust, hopefully she stands the test of time.
The PCS controller is an awesome piece, contact Scott at Destroked for one as he is a dealer for them. I can also email anybody that buys one from him my file to get you going.