I am running a pair of Middle T’s with a single 3B2 in a room 16’ x 23’ x 9” with no issues but I already had a pair of 3B2’s. If purchasing new I would get the 4B2 or 4B3 and Be done with it. If purchasing used, a super deal on a 3B would be more compelling than a ok deal on a 4B to me but as always, YMMV.