I have a masterpiece TT4. I feel the wood treatment, whether its the roasting or the vibration, has definitely altered the wood...it feels old and more "dead".
Feel aside, I hypothesize this changes the balance of the harmonics between the fundamental vs the 2nd and third harmonics. It's subtle, but I don't think I'm imagining it and I'm very aware of the placebo effect I could be projecting.
Any marketing materials I've sen on the treatment seem to be reaching IMO though. It's not magic, and any sound change is subtle at best.
By contrast, I have a few neck through wenge Warwicks...wenge all the way through the body, and they are "springy" feeling in comparison...my theory is the specific "spring" characteristics of that wenge have a resonation frequency somewhere around the 3rd harmonic and get that characteristic Warwick mid bump. You can almost feel it though the neck, the buzz.