I can strongly suggest to seek out a pair of Thiel CS 2.4 loudspeakersYes, this is what I moved to after the 2Ce Sig IIs (I had the original with the plastic midrange diaphragm, current production uses the "tri-woven"). Anyone buying used I strongly recommend the CS2.4 over the Sig IIs (altho' make sure your amp is comfy with a 4 Ohm load!). The Vandies are fantastic as I wrote earlier but the CS2.4 has more bass definition (2Ce does go a bit lower, tho'). My SE version also has more resolution and greater transparency. You can get used CS2.4s in good condition for about $2k, sometimes less. Rob Gillum has the upgrade kits to convert to SE equivalency. Tom Thiel will have an even better upgrade path for the XO later this year. I suspect you'll have to move up to something like the 5 Carbon or Vivid B1 to top a tricked-out CS2.4.
But if you're committed to new, it's *really* hard to beat the Sig II.