My car is running 250kw on a PowerFC, runs great. Sean's car was running somewhere north of 400HP on PowerFC but I think he did make some reasonable gains when he moved to a Motec (unverified).

I love my PFC and especially the FC Commander but the PFC won't retard timing like the stock ECU so you do have to watch carefully for any knock warnings (have blown 2 motors - cracked ringlands - with PFC )