I don't have them yet.
I've only heard the old Classic T2 towers a few years ago when I was auditioning Revel, B&W, KEF, Linkwitz, Wilson, etc.
My impression of the old boxy Classic T2 towers was that they sounded utterly amazing in terms of treble, midrange, and bass, but they looked really ugly.
So the SX-series fixed the aesthetic of the old classic T-series.
Some people say the
Reference T (SX-T2/
R) sounds significantly better. But I am reticent to implicitly agree since the standard Signature T-series already sound astounding. I'm just thinking, "How do you improve on such amazing speakers?"