Cars like mine --> Trannys running 600WHP without any reinforcements. I know a lot of Skylines are out doing the same thing. My car is factory 300BHP. I can’t speak for many other cause I’m not sure but my 1982 Datsun 200SX (S110) was running 160WHP with no problems on long hot drives. That’s all the way up from 102BHP. No change to tranny internals at all. I won’t say in the open what my Z32 is doing but I’ve tripped it to London and back a few times on hot days non-stop and the tranny ran without any issues.