A better 15" sub

I have this sub 15" Hifonics Brutus, nice lil budget sub thats pretty decent. I wondering if any of the below options would be a step up as far as quality and spl. Im looking for more spl than sq, but not sound too bad. I want to get 1 for now, and possibly at a second sub later. I have aprox. 900wrms to work with for now. Putting in a 3 cubed, tuned 33 hz. Would i be better off sticking with the sub i have now and getting another one or getting one of the below options, open to any suggestions.

1.RD Sonance $175 shipped

2.AQ SD2.5 $185 shipped

3.Diamond Audio D6 $190 shipped

4.Re Audio SE $130 shipped

5.Alpine Type R $150 shipped

or any other quality drivers out there.

trying to stay up under $225 for the sub.

Thanks for looking and helping me out.