I'm not sure if this has been talked about yet, but!
I'm currently playing E:D through Steam, bought it on the Steam release way back when, but I pre-ordered Horizons through FD's website, as pre-ordering isn't available on Steam, and I haven't heard anything about when Horizons will be available through Steam.
My question is, will I need to re-install/delete anything, or will it be as simple as installing Horizons from FD's store page and playing from the regular launcher?