ARC VSi55 integrated or VS55 plus Preamp?

I currently have a VSI55 with KT120's. They are powering a pair of Focal micro utopia be's. I wonder what I might expect if I were to have the same amplification mated with a full function pre for example an LS27? Eventually I would like to have more power for the Utopia's. If I could trade my integrated straight up for an amp and allow the freedom to acquire a pre, I could eventually acquire a larger amp when funds allow. My other equipment includes a Michell Orbe, Soundsmith Voice, pair of JL F110's and an idle pair of quad 57's.