By the size of your room, I would recommend dual subs as the best way to have a more even response in your room. Judging by the reports/reviews of the MFW-15, this would be the way to go, especially if the new amps do in fact repair the problems they were having with them or go for the tried and true Hsu in dual form.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70