I used to own a pair of Model 1 sigs and the best amp I ever used was a BAT VK60 (used under 2K). TWL is right about finding a suitable tube amp under 2K with the above exception. The best solid state amp that I tried with great results was the Sim Audio W5, 200 watt amp. I've read that the 200 watt McCormack also works well. I would stay away from the Bryston 4bst as this amp is veiled sounding with these speakers.
If you like the Totem sound, try the Totem Hawks. They are like the Model 1 sigs, but have more bass, are a bit warmer and are easier to drive.
If you like the Totem sound, try the Totem Hawks. They are like the Model 1 sigs, but have more bass, are a bit warmer and are easier to drive.