I have been pushing my trans for about a year now.
FBO+Meth on 93 I made 401/433 - Ran this daily for about 6 months
FBO+Meth on 109 I made 433/473 - Ran this at the track 3-5 times
Now I am running FBO+Meth on a E85 mix. I have not put the car on the Dyno yet with E85 but I have to guess it to be around 420/450 area and have been running this for the past 4-5 months.
From what I have seen, it looks like the bigger issues start to poke through once you go with a turbo upgrade and run 500+. I still think that this trans can hold 500+ as long as the boost is controlled well post shift so it does not take on all 500 at one moment.