Upgrading from Thiel CS3.6 to Avalon


I'm considering upgrading my 20yr-old Thiel CS3.6 to Avalon Opus or Eidolon. Do you guys think it worth the upgrade? My listening room is measuring 17(W)x13(L)x8(H) ft.(speakers along the long wall) Which one(Opus or Eidolon) makes a better choice?
BTW, my other components: Esoteric K-05, Gryphon Diablo, audience Au24e XLR and cables.
Thanks!!
tomatowu
I went from 3.6s to CS6 and to Salksound Soundscape 8. I am very happy with my latest purchase. IMO, The Salk is much better in every way.
Tom-

Thiel speakers are a unique beast. Upgrade to the CS 2.7 or CS3.7 model.

Keep me posted on your decision.
I owned Thiel 3.5s for ( 8yrs ) Loved Them! Drove them with Forte' monos (Nelson Pass design) and Spectral electronics. Thiels; at least the Legacy models are as you know, as an owner, are what everyone claims. Very hard to find a speaker as good or better for the money. I tried Pro Ac, Wilson, Sonus Farber but finally settled on Avalons. Opus w/ carbon woofers. The Eidolon come up for sale fairly often, I have never seen a pair of Opus for Sale. The Opus will fit your room well ( my room is 13w X 23L  X 9h ) My opinion- The Avalons are superior. Better imaging / soundstage. Smoother top to bottom, no need for a subwoofer. wigs comments also apply. The Eidolon; I heard both at the dealer many times and (6wks) in home demo. But I settled on the Opus. They will fit & fill many rooms. Your equipment should mate well. Now that Jim and Kathy are gone. ( even though Thiel seems to be supporting the Legacy models ) I think you will find the Thiels to be getting long in the tooth and service to become problematic in the future. 
If you can find a pair of Opus w/carbon woofers ( ceramic lack in the bass) You will never look back.

Best Wishes on your Journey.