Well, it all depends on how the amp is configured, you can efficiently power loud ass subs with 800watts and you can totally under power your subs with 2000watts (if you dont know what you're doing)
I would suggest getting a big amp (1000w+) and 2 of these 800w kickers you were talking about and that will give you enough bass that you wont even be able to turn it all the way up without making your ears bleed...lol
wire them in series to lower the ohm load and set your low pass filter to about 150hz with the gain at like 95% (to reduce distortion) then if youre amp has bass boost programming, set that to the level of bass you are comfortable with.