Sorry!, let me clarify my posistion on the 4T80e: I beat the piss out of it all the time, never lets me down..It does have a few issues, almost all are related to some sort of electrical sensor (ISS).The gears,bands,clutches etc rarely fail, I've maybe seen a handful of posts regarding these compoenents.
So yes, the 4T80e is a beast, but it is maxed out @ 305ft/lbs...If I get time I will try and dig up the link on Caddy-info. I believe it is from a GM tech website and it notes that the 4T80e is currently at it's limits...I belive Mark was afraid to drive his STS in anything but second untill he got his (Tranny) rebuilt, as I recall the people doing the job said the increase in torque would rip the Tranny out from under the car..lol. BBOB always said a stock N* could take 400hp (or more ?)...The 4T80 is a different story