I concur that Brystons are a good match...in general.
I am running CS5 with Brystons 7b in parralel mode. I tried running them with 250 watt ICE power class D amps, but there was absolutely no guts or life or depth to music. My only issue when running 7B's is that bass is a bit exaggerated, especially at the sub harmonic level. I don't think this is a result of room or treatment due to having experience with several other speakers.
Perhaps this relates to what Tom has stated earlier:
A) CS5 would have been a good candidate for bi-wiring
B) CS5i have more articulated lower and lower mids.
Question: would it be a worthwhile endeavor to search out replacement drivers to convert these to CS5i upgrade?