Michael,

You posed the question whether anyone has experienced the upgrade from 5000's to 5500's. I had the opportunity to do that upgrade last fall and the results have been nothing short of spectacular. While I was always satisfied with my 5000's, the 5500's opened up the sound stage and brought real bass to the system. IMHO, I would estimate that the 5500's give about 85-90% of the performance of the 6000's. That being said, the upgrade was not subtle.

The best part of the upgrade process was the price. I ran across these on eBay and although my bid of $4550 US did not meet the seller's reserve, he was so anxious to sell, that he offered them to me at that price! These were less than a year old and were the 24/96 version! I still can't believe my luck. Good luck in your search.

Rudy