I really haven't been in the HT loop for a while. It is a shame what's been happening with AV123. I have purchased a few products from them over the years, including a mfw-15(no problems with mine after a year and a half).
To the OP: I guess you have your reasons for wanting 2 subs. One SVS ultra13 might do the trick. I have owned the pb12-plus, vtf-3 mkII, and now the mfw-15. They have all been setup in my 15 x 22 x 9 listening area that opens up to 2 other rooms. They have all sounded good, but I personally would give the nod to the mfw-15 for sounding the best. I don't think you can go wrong in which ever direction you go.