Internal Speaker Wiring ??

Finally, somebody noticed. Also look at the wiring from your amp board to the monstrous gold binding posts. Both runs are short , however, and generally based on engineering principle like adequate wire size to handle the expected current. With even decent wire, voltage drop at any frequency in that length is absolutely minimal and there is minimal exposure to stray pickup, especially at the signel levels involved. Good wire and good connections are technically desirable, however. If you are using LONG speaker cables, then technically there is the potential for coloration because of possible resistivity variation with frequency. Having one-foot long buss bars from your amp to speakers is ludicrous. Good connections are the most important consideration in short runs (actually important in any length run). IMO :)

I've never owned Thiel's and I am a little surprised to hear what you said given the extensive cross-over design they use--why go cheap on the wires? It does make a big difference as to which driver you are talking about. The tweeter may have what appears to be wimpy wire, but actually could be a very pure copper or silver that is well suited to the task. On the other hand, the woofer, will draw a much larger load and should have beefier wire. If it doesn't you could always fix that yourself, but be cautious as many designers figure in the wire (resistance) as part of the cross-over (network) design. I have no idea what Thiel's intentions are.

Abstract7's comments to first check with your speaker manufacturer is excellent advise. A number of years ago I totally rewired my Snell speakers, using the best Audioquest wire available. I was certain that I would get a terrific improvement, replacing the poor quality and puny wiring supplied by the factory. What in fact resulted was the most terrible tonal balance and phase shift you can imagine. I wound up returning the speakers to the factory. I expected that they would remove my wire, but instead, measured the speakers, factored in the changes, and swapped some parts in the crossover. After my speakers were returned, (with a substantial invoice), I was so mad at myself, that the improvements were a disappointment. The moral? If you change, be sure the factory says it will not alter the speakers electrical function in a negative way. By the way, my results have been just the opposite when applied to preamps and amps. I have rewired (replaced stock wire) in about a dozen units, and have always been rewarded with stunning improvements in sound, across the board. Best to you!