1200 rms

i have a FI Q 18 fully loaded in 5 cubes sealed. i have to pretty much max out the level on the amp and all bass boosts to get the sub to even move like its supposed to. Its running off a 800 amp batcap. so i dont think power is the problem. but the sub def seems to need more and i dont want to...

As the title says... looking for a PDX-M12 at a decent price... will consider other amps pushing around 1200 rms though. Must be in good working condition...preferably 2008/09 or newer thanks!