An audiophile friend has a pair of the C1's. Overall, nice sounding speaker that plays well (no pun) w/ both CD and Vinyl.

The C2 reference is a big step-up from the C1. I have been wanting to hear those C2 speakers.

Ask the shops if they will let you take the speakers home for an audition. Moving all five speakers from two companies might be hard. But perhaps the two main channels will be enough to guide your choice. After all, if you don't like the two mains, three more won't help. 

The Dynaudio C2 is a fine speaker, but in my opinion there are 3 or 4 better speakers for less than $10k.

I would never pay $15K for those speakers.

I recently looked around and listened to a lot of speakers, and I found that the Vandersteen Treo speakers were by far the best-sounding. I now have them.

I would suggest that you check out the Treos before committing to anything else.

They are stunningly good; the best I have ever heard (and only $6000). They are also quite beautiful, and you can order them in your choice of 7 or 8 different lovely woods.

You should read John Atkinson's review of them in Stereophile.