I found my vt100 lacking in power to drive my vandersteen 3aSignatures. It could drive my virgo's fine. It would probably be cheaper to add a subwoofer, or go with a more efficient speaker. A big problem with large tube amps is they can be VERY expensive to retube. Some of the 150W+ audio research amps get into the 900-1200 range to retube. I don't think you can get away from the heat problem.
Best tube power amp(s)-B&W Matrix 802-S3
Right now my system consists of the B&W Matrix 802's, a VTL S-T 85 amp, & VTL TL2.5 pre-amp. I love the sound actually, except for the usual faults of a smallish tube amp to drive big spkrs.--inc. some lack of bass, & perhaps not the ultimate soundstage or ability to handle large scale symphonic works (but a sweet sound nonetheless). My possible choices right now are C-J premier 12's, ARC VT100 Mk.2, or VTL mono-blocks like perhaps the 175's. Have also considered s.s. amp like C-J MF2500 or Bryston mono-blocks (whew! talk about the upgrade bug!). This is for a 12X18ft. room. I am very into the tube thing right now after my experience w/the VTL's, but could possibly go for a S.S. amp & keep the tube pre. Heat is an issue as well.....Any advice would be greatly appreciated! Thanks, steve