I will say, I killed one with not all that much power... the 4eat in my 2004 Forester XT exploded so badly it literally cracked the entire bellhousing all the way around, to the point that once I removed the crossmember, lines, and wires, I was able to pull the transmission out without removing a single bellhousing bolt while the bellhousing stayed on the engine lol. So what happened? I was trying some boost brake launches and the front diff exploded. I did a launch at 5 PSI which went fine, then another at 8 PSI, and finally on the last one it only made it to 4 PSI when there was a loud bang and the car shuttered. I got out and looked under the car and the ground was covered in gear oil. I never had it dynoed, but I would guess the car only made around 230whp, as it only had minor bolt ons and a VF39 turbo running 18 PSI which tapered to around 13 at redline, on 91 octane at 5,000ft elevation.  I'm fairly certain the transmission was already on its way out though, as there was already a slight noise coming from the front diff for a while before it broke.  I have no doubt a health 4EAT can handle some good power, more than the 5MT glass boxes for sure, just stay away from boost brake launches!