Reaplce Thiel 3.6's Tweeter

Just to state the obvious: have you asked Thiel? One reason why the tweet may sound hot is the soft xover -- if you're a diyer try a 8-10ohm resistor on it. If NOT a diyer DON'T do anything. Just place the 3,6 w/out toe-in, then slowly introduce toe-in ~80 degrees b/ween the two spkrs or to wherever it starts to become too hot for you.

BTW, the 3,6 are not the easiest of "affordable" spkrs to drive...

I can only say since you seem to like cones you might want to try Thiels more expensive model's, or maybe move to a planer speaker. Would all depend on your listening room and type of music you enjoy. I have found the best way to enjoy your system don't fix it unless it's broke.I have been using the same speaker for around 5yrs and still enjoy them very much. I found just moving them and room placement with an eye on room acoustic treatment as helped greatly.

I don't think you can do better than what Jim Thiel has come up with.

Amp choices can be very personal. Thiel doesn't go as far as to make actual recommendations, how ever they suggest that they have especially enjoyed results with: Ayre, Boulder, Classe', Conrad-Johnson, Krell, Levinson, Pass, Theta, and VTL. Their web site also offers less expensive alternatives. IMHO, Thiel's demand quality amplification. The 3.6's will require an amp to provide plenty of power into low impedances. Be especially carefull when opting for tubes as the difficult impedance load of the 3.6's will require very powerfull tube amplification. Of course power requirements will ultimately depend on your room and desired volume. The Thiels' also have wide dispersion. Perhaps room treatment might help. Try to avoid too much or for that matter any toe in. Good luck.

Of course the easiest way to resolve this issue might be with some equalization.