Having rocked a pair of Thunder's, 4000 series, I can attest to how hard they can hit, even with an inferior amp. But if you have $200 to spend on each, you have alot of options, especially since you want 10's. What is your preference, spl or sq? I know even us sq guys want some nice bump, that goes w/o saying, I just need to know if you want more spl instead of more quality sound.