I use the TC625i as my surrounds with Polk RM8s for the front, which are the same speakers in the RM95 package.  My sub is a Velodyne Impact 12.  All of it is being driven by an Onkyo TXSR607 receiver.  Using the Audyssey EQ calibration the receiver shows the TC625i frequency response goes as low as 50Hz.  I have the speakers set as large and I am really happy with the surround performance.  The RM8 perform exceptionally well with them but to be honest, for my next surround sound project I will be using the TC625i for all five channels and another Velodyne Impact 12 in our large Master Bedroom.  The wife was more impressed with the in-wall speakers than the RM8, and I'm satisfied with the sound quality.