if you can get 800 total rms at 1ohm and 600 total rms at 2ohms, I would suggest getting a sub that would make the amp produce 600 rms. reason being is because although an amp is "stable" to 1ohm, it will run much hotter and will reduce the life of the amp.

time to research subs that are 2ohm dual voice coils at 600rms.