You may well find the Salks increasingly satisfying over time. Like some, I suspect that much of what commonly is reported as speaker "burn-in" instead reflects the assimilation of the listener to unfamiliar sound dynamics. It is unlikely that your Salks will lose much resale value in the meantime, so little need to rush. As for the Sierras, perhaps the lesson is that you just love that particular sound, and if so, why even upgrade to the EX? You may invite the same phenomenon again, particularly going to tweeters more similar to those in the Salks.
Magic returns in seldom used bookshelves?
Has anyone else pulled out a pair of less expensive ( in this case a pair of Ascend Sierra 2 non ex) speakers and really consider returning them to the "main" system. I currently have a pair of really really nice Salk Song 3 BeAts ( mine are the ones on Jim's site in Fireburst Carpathian Elm Burl...gorgeous they are) and while I really really like them they have rarely if ever given me that "chills big huge smile" on several songs like the little Sierra's do? Everything else in system has remained consistent, but man on man, am I crazy to be considering selling my Salks and upgrading my little Sierra's to the new ex version for a nominal cost?