Your Threshold amp should be able to drive almost any speaker, they are excellent amps. I find Threshold amps to sound a little on the lean side and seem to sound better with a fuller, slightly warmer sounding speaker. I have a Threshold S350e amp and Fet10e pre myself and was driving a set of Infinity Renaissance 90s for the last 10 years. Although the Threshold amps have high current capability, Infinitys are not the easiest speakers to drive and I always felt that they sounded a little lean and didn't quite have the punch and dynamics I was craving. Last fall I found a deal on a demo pair of JM Lab 946 Electras and man what a difference. They are much more efficient than the Infinitys were, the music now sounds much more alive and dynamic. I have heard people say the JM Lab speakers sound too warm or full but not with my Threshold, perfect match. If you have never heard the JM Lab Electra series before I would give them an audition, almost Utopia quality sound at a fraction of the price. Of coarse this will also depend on your room as well. There is something to be said for efficient speakers though, even with a high current solid state amp. I find the presentation to be relativley neutral with these amps very similar to the Pass Labs X series. I would just audition speakers driven only by a good quality s/state amp and go from there. Hope this helps.
