Actually, I haven't heard them with the upgrades. What's involved?
You can do the biggest bang for buck upgrade, which is to replace the resistors and capacitors on the stock XO board with Mills resistors and Sonicap/Erse caps, while adding bypass caps (Sonicap GenII or Sonicap Platinums). Or you can take it up another notch by building a new XO with Mills and Sonicaps, and upgraded inductors and point-to-point wiring.
I did the bang for buck upgrade on a pair of X-LS Encores with Gen II bypass caps, and it really brings out the clarity. Those speakers are for sale in the "trading post" section by the way. (Shameless plug.

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