I did a search before i posted and all i could find was info from Hinson who used a ls1 and not a rotary.. but at what HP levels should i be concerned about my rear end breaking... I am building a 13b with the bnr stage 3 twins and im shooting for around 415hp to the wheels.. if i bolt slicks on I dont want my rear end to shoot into pieces.. anyone have experiance on if i should be safe or not... or should i upgrade the rear end before i do the turbos??

 

I don't know what search terms you used but there is a TON of threads on this topic, including one from a few days ago:

https://www.rx7club.com/showthread.p...ght=diff+power

EDIT: the short answer is no way in hell will the stock diff take that kind of abuse