Best affordable amp for Thiel CS3.6

I have a pair of CS3.6's, which I am currently driving with a pair of Adcom GFA-555II's in bridged mono mode. While I am fairly happy with this setup, I realize that the Adcoms may not be in the same league as the Thiels. Any suggestions as to what amps mate well with the CS3.6's? Ideally, I'd love to find an amp (or two, if mono) for under $2,000, but if it's worthwhile, I may go higher. Obviously, if there is a great option out there for less money, I'd be even more interested. Used gear is fine with me, if it is quality gear. I am also considering modding my Adcoms to smooth out the mids/highs and add a little support in the low end.

Another consideration is that I am currently using an Adcom GFA-2535 for my center channel (Thiel SCS3) and surrounds (AR TSW-110), and since it is nice to have matching amps for HT, I'd probably have to add an additional amp or two (eventually).

My sources are currently a Denon DCM-460 and a JVC SA-600, but these are likely to be upgraded in the relatively near future. Both are sending digital outs to my Rotel RSP-1066, which handles the processing.

Thanks for any input/advice.

Tom.