I have only ever heard of a Supra diff breaking where one of the covers was not used and the diff was converted to run a cossie, it was also on a drag strip. I believe that up to 1000 bhp has been put through the Supra diff. There is a member on here who used to have a very high powered Supra and he spanked it a lot. MT has a customer with 1000 bhp drag car running his Supra diff kit.

No doubt some people can break them but they would probably break anything and there will always be the odd faliure with some units but I know for sure that less Supra diffs break at 500 bhp than standard cossie ones.

If we look at this thread Ian has busted 2 front diffs using slicks on track but the Supra diff is intact still.