Depends on what you are looking for. I would probably say that Xtant would be overkill for those speakers. PPI and MTX products are on
www.ubid.com often. You can get some really good deals. There has been a 5 channel MTX amp on
www.ubid.com that may interest you. It's about the same price as a 4 channel amp and gives you a 100 watts or so to send to a subwoofer.