Not so much of a push, im aiming for 500hp with mine (dropping down a turbo size or 2 from that typically found on 600hp 13B's) for the exact reasons a 600hp twin rotor aint suited to drifting. But it's still track/dyno only setup at those power levels.
But you are right, why ruin an rx-7 with an LS motor- just buy a vette perhaps (in the same regard i'd never ruin a vette or mustang with a rotor). I much prefer Mad Mike's quad rotor drift 7.
Anyway I don't really rate the rx-7 driver at all, but he's learning (everyone got to start somewhere). From watching a reasonable amount of drifting american's tend just powerslide their way into drift

[}:)], makes you wonder if they'd cope at all with a 180hp ae86 or something. No one beats the japs at making cars dance.