The T56 MagnumXL has been performing very well in high HP applications at tracks. It takes a lot to tear one of them up. You may wish to talk to Brandon Alsep to find out what he is running in his NMRA Coyote stock class setup. I know its a stick car and he runs in the 10's with it.

Draggin 50 can tell you what was in his 800ish RWHP 04 Terminator that held up well also. I never recall him having a trans issue and he beat it like a rug at the track.