Hello all, I am thinking about the upgrade. I have 2 pb2isd's right now and i am going to upgrade. I have a theater room that is 22x17x8. I know that I "do not need" anymore than what I have right now but you know how that goes. My options are to sell the 2 pb2isd's and get 2 b4plus's or either add 2 more pb2isd's. Going with 4 isd's would be much cheaper, but would it be possible to get all four of them to sound right together? Also if I could get them all together properly, how would they compare to 2 b4-plus's? Any help would be great. Thanks guys.