I did a post a while back about comparing vinyl and CD versions of Miles Davis' Bags Groove. (I think that's which one it was...it's getting late.) Anyway, there were both XRCD and K2 versions. The K2 version appeared to be from a later remastering...as best I could tell. Whatever the reason, it sounded better than the XRCD, in my judgment (and was the best sounding of the bunch, including the Lp version I was using at the time). The XRCD version was noticeably brighter and even a bit irritating (to my ear).
I wish I knew about other CDs that used the K2 processing, b/c they seem to be darn good CDs. I have several K2 jazz items from Prestige and I think related labels, and I think at one time they were noted on the websites for those labels. I know there were some other Miles Davis, and Thelonious Monk, and I believe Bill Evans titles, but that pretty well exhausts my knowledge.
Good luck.