The best center for Paradigm Ref studio 20's v2?

currently using an older, smaller B&W cc#3 but have need for better sound. Have been using a Marantz SR780 amp, but just purchased a Marantz SR5004 for combined music and home theater. Recently downsized from a home with dedicated 2 channel as well as video. Was using Cambridge 840A v2, which sounds great! but no longer have room for both systems. my current set up will have to be a 3.1 due to physical limitations.
thanks,