I would be wary of any tube amp with these speakers to make them perform at their absolute best.
As at 4khz they give a nasty 3ohms and -55 degree phase angle. Which would be more like a 1-2ohm load as seen by the amp.
An amp that "almost" doubles it's wattage for each halving of load impedance down to 2ohm would be the amp to look for.
EG:
8ohms - 100watt
4ohms - 200watt
2ohms - 400watt
http://www.stereophile.com/content/martinlogan-montis-loudspeaker-measurements
Cheers george