Need help picking new subs for current setup

Currently, I have this setup:

Planet Audio 2000W Amp

MTX Terminator 1200W Subs + Box (scrub setup, I know)

I was wondering what you guys would suggest as replacement subs because the current ones are not cutting it anymore (that and distortion and general shitness).

I want to pump as much power to the new subs as possible and get as much bass as possible but I don't want to spend $200 on a subwoofer that will be underpowered.

What would be the best choice to get as much out of the amp as possible? I don't really have a price limit.