Worst advice to date. Small rooms are an acoustical war ! Read
Welti/devantiers paper on multiple subwoofers and mode canceling methods.
Check out the graphs i posted in my link in my signature. So many guys purchase one very expensive sub, never measure it, use a method for good placement which entales crawling around on the floor.
Use part of your budget to purchase some measuring tools so you can continue the science that continues to make great subs. OmniMic is a great measuring tool !
As of Jan 2017, im still looking for (1) Outlaw M-200 mono amp, and a used Marantz 7010