I drive my 3.6's with a conrad johnson premier350 and it does a very good job. But really any high quality high power amp will do as Thiels love power. In any case quality over quantity is best.
I used to use Parasound JC-1 mono amps to drive my CS7.2 with good result. The CS 6 and 7.2 have a lot of similarities, especially the impedance.
I am now using Lamm 2.1 monos as they seem to match the 7.2's tonal balance better. But at about $4k used, the JC-1 is really good. IMO, big powerful solid amp will do it, but matching the speaker's tonal balance is the key as this varies among users' preference. I would stay away from tube amps unless you can audition it for a good period of time to test it out before buying it.