For tight non-boomy bass, start with your room. From my limited experience listening and playing it seems the room has the largest impact on the sound quality, then comes the source and finally the components and speakers. But, still learning here... perhaps in addition to upgrading your amp room acoustics could be improved. I know in my setup my room is the weakest link. Also, if you listen at loud volumes I recommend bi/tri-amping, or just because you can.

But go borrow an amp and try it out. My B&K ST-202+ is rated 200x2 and costs under $400, if you can find one.