You might try changing the speakers first and see you get the result you want. The CJ equipment shouldn't be forward at all (well, a little, but it should be warm enough to compensate nicely) and in just about every system I've heard with your Thiel's, I thought they were on the bright side, but not at all shy on bass. It could be that in your setup, the bass is getting diffused somehow, or that you have them poorly placed to bring out the bottom end. I agree with glen that some repositioning might be in order before you take the plunge into new equipment.
As for recommendations, I can't be of too much help with the specific equipment you mentioned, although I'm certain that you'll find more bottom end slam with the Bel Cantos than with the CJ amp. However, you'll also find that the timbre of the sound will change as well, so you might want to try them side by side (if possible) before you make any firm decisions.
-- Ken