What do you mean "more than efficient"?

I mean if you are going all into stock racing right now and set on doing the whole cycle charging but dont want to blow 800+ just on the charger setup, just get the icharger first and build yourself a cheap resister bank discharger. It will still function the same but you are wasting a lot of power (but probably a good heater during winter) but to be honest, you wont be paying the power bill at the track anyways.

And if you move away from stock and into mod, you still have a capable charger for all your needs.