My experience with aTCI trans was not good.
But, that was a long time ago. They have probably got a better product today, or they would not be in business. But here's my advice, for whatever it might be worth. Instead of buying from a major brand tranny builder, talk to some of the racers at some of the local tracks near you. Find out who is building their trannies. There is usually 1 or 2 guys who build for the guys in the area who race.
I began doing that years ago. The local guys built trannies that lasted. The TCI broke quickly. My tranny guy now, is a local and has also been a Pontiac racer for years. He can build a tranny that will hold up behind my 455's and he is MUCH cheaper than the major brand names.
So, it may be cheaper to buy the good parts and have a local guy do the work. If a local builds 'em that don't last, then soon nobody will by from him. So I'd check around for local guys that have a good rep with the racers.