SWA is the budget line of alpine, and @sphan519 already pointed out you've only got 250rms on that thing.
for the subwoofer you're gonna want a type R if you want anything worthwhile, and type X if you can afford it.
other notables: rockford fosgate punch 3 and higher, JL w3 and higher, sony GS, phoenix gold Ti and higher, JBL gt0 and higher, etc.
the boss amp you have isn't CEA certified so i'd be wary of its power ratings.
also it is advisable to go with class D for monoblock subwoofer.
hope this helps.