Elevick, while perhaps not as sensitive as some of Thiels newer models, I think the the impedance load of the Thiel CS 1 is lot easier on amplifiers than the newer Thiels.
Raya, if they're not broken, I'd leave them alone. Though perhaps undervalued on the used market, they're probably not worth $400 on the used market, so the repairs/ shipping appears to be a poor value. They're still good speakers, and I'd caution one against assuming some newer speakers sounding different as actually being better. As much as you might trust your dealer, at this price point, and considering the value of the dollar today as compared to your 20+ year old then costing $1000 Thiels, I don't think the technology has improved that much. I'd imagine you'd be getting a lot less for your 2011 $400 with a new speaker.
Raya, if they're not broken, I'd leave them alone. Though perhaps undervalued on the used market, they're probably not worth $400 on the used market, so the repairs/ shipping appears to be a poor value. They're still good speakers, and I'd caution one against assuming some newer speakers sounding different as actually being better. As much as you might trust your dealer, at this price point, and considering the value of the dollar today as compared to your 20+ year old then costing $1000 Thiels, I don't think the technology has improved that much. I'd imagine you'd be getting a lot less for your 2011 $400 with a new speaker.