I just saw my recorded episode of Engine Power. They featured John Urist from Hellion and Chris Groves from Dyno Edge. Both from here in Albuquerque. Wow-900+hp! Nothing else to say!
A friend of mine just tuned a Hellion twin 62mm Boss 302 on E85. Return fuel system (I don't remember which one) with ID1000 injectors (maxed out), 14lbs of boost, it made 918hp/758tq on a Dynojet here in MN. As far as I know, the engine and driveline are otherwise stock (stock clutch even, for now...lol).
Lots of twin turbo mustangs out there making north of 900rwhp but not many seem to run a good number at the track. Just a few from what I see. That tranny takes a little time and knowledge to make it work.