This is why I don't understand the fascination with going the V8 route. If you swap the auto tranny for the AR-5 5-speed you keep TOD, get a more power-capable transmission, and you can bolt up to the Ecotec turbo 4-bangers that (when tuned with the factory kit) make well over 300 HP. That gives you equivalent power plus less weight and better fuel economy.
But you guys are the experts actually turning wrenches. Is there a hole in that theory?