I currently have ML Vantages paired with a McIntosh MA6500 integrated (solid state/200wpc) and an Oppo 105. This setup works very well for me. The Vantages, as well as your Theos, need a lot of clean power to make them shine. I've never tried tubes but you will need a lot of power/current to make your speakers sing. I have heard my system with a 100 watt Anthem integrated as well and I did not like how dark and rolled off it was. The MA6500 is a good match, IMO, with very nice midrange, strong bass (if its in the material) and good clean airy highs. I have never had any problems with "circuit protection" like terry9 mentions above. And I use my system as both 2 channel music and 2 channel home theatre. When I watch fun movies like Casino Royale and The Matrix, the volume is up to 12 PM and the sofa is vibrating and the Vantages have never shut off or sounded compromised. They perform very nicely at high volumes, whether playing music or movies.
The 105 works very good and I'm super happy with it. I'd buy it again.
For more help, check out MartinLoganowners dot com. You may find threads of interest there. Good luck in your journey.