S23 above was actually listening to my speakers which were upgraded from RM22si Signature MK1 to MK2 for $500. In this procedure, the tweeters and crossovers were replaced. The difference is subtle, but quite noticeable. The MK2 has better air and separation between instruments. It also has better resolution with a cleaner sound. The sonic balance remains very much the same. Jeff, who is a very nice guy, did not believe that a break in was necessary after the upgrade, but I found that the speakers did not really settle in until after good 100 hours of listening. Initially, they produced a harder and tighter sound with more trebble emphasis (this was regardless of cables used). After settling in, they produced a pretty remarkable sound. The RM22si Signature remains one of the best speakers I have heard at this price range with a sonic balance that leans slightly toward the cool side. Matching them with slightly warm sounding gear would be an advise from me.