I don't have experience with VTL, but did run Thiel 2.3's for three years with an Air Tight ATM2 (80 watts/ch) in a pretty large room (5000 c.f.). The amp never ran out of steam and the overall sound was very, very good.
On the contrary, I agree with other posters, that Thiel 3.6's will eat your amp's lunch. I upgraded to CS6's last year and spent 10 months dealing with buyers remorse for pairing my once butt-kicking tube amp to the power hungry CS6's. What a disaster. The bigger Thiels need LOTS of solid state power to sound their best. Good luck!