Not sure why people are putting MTL anything in our transmissions as it is 70W80.
There is probably a reason why your oil broke down Jeff.

MT90 is 75W90 and much better suited to the heat of the track.

I've personally been running redline shockproof heavy in my TC for 38,000 miles and over 18 track events. No problem yet.

I've also been running redline 75/90 in the rear diff for 38,000 miles and over 18 track events. No problem yet.

I ripped the teeth off 4th gear in my 6spd last year from heat from the track breaking down the oil, I was using BG2 at the time. I now use a mix of redline shockproof heavy and redline MT90 in my 6spd. It's been working amazing, espically when warmed up.

Like BBYBruno said, most of the redline stories are from people trying to put a round peg in a square hole.