the only bad part about at 4 ohm is that the amp is rated at 300rms.

Sundown Audio SAE-1200D - SSA Car Audio Forum

I have 2 subs not one.

I have heard the sundown is a really good amp that is very stable even at .5ohm but it voids the warranty.
I also got 2yr warranty on it because it is new from an authorized dealer as long as I dont go under 1 ohm.

I think 1 ohm is good but I dont know if I can send it 800 watts and not the full 1200 watts that it is rated at.