When I went from a 350-ish sub (PSB 6) to a better (SVS PC+ 20/39) sub, and did my best to place it in exactly the same location in the old house, I felt the results were considerably better. I think the difference was the extended LF response, which gave the impression of more bass without having to turn the levels up.

Or you could just get some butt-kickers.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8