The ones that take a beating are on extremely light builds. 3.6 pullies, no cam/no rockers, etc.

The ones that hold together and take a beating in a mildly built car don't do it for long. My last GP build had maybe 325 WHP. I got maybe 10k on the build and the trans started to slip bad.

Simply put, there are no factory freak/bulletproof 4T65E transmissions. They will all fail with any significant amount of power increase. Hell, the stock GXP transmissions fail all the time, and the LS4 only has 303 crank hp.