Reaplce Thiel 3.6's Tweeter

Same goes with me, I agree with them completely. If you like you could try some felt if you like around the tweeters and if you don't like the change just remove. But to try another tweeter in place of the Thiels? Better to just purchase another speaker if your not happy with the top end.

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.