Lightning quick DYNAMIC amp in the under $1000 range

aberyclark, just to be clear, did you use the Prebox s2 directly into the STA200, without SYS? I am asking as I thought about purchasing the prebox to use directly  with my STA200. Thanks.

Class D Audio. High power, great price!
https://classdaudio.com/class-d-amplifiers/sds-audio-amplifiers.html

bstatmeister OP
May need to add the Schiit Aegir to the list now that it’s available. It’s $100 more than the Vidar, but supposed to sound better overall as long as you don’t listen at high levels with inefficient speakers. The Vandy 2Cs are 88db efficient and I do like to listen loud once in a while, so if I wanted to go this direction, I may have to monoblock them, however if I do this

Don’t!!!!! bridge them, you gain wattage only, sound quality takes a hit.

Horizontal Bi-amp instead, put the Schiit Aegir on the mids and highs of the Vandersteen 2C for the best sounding Class-A mids and highs, and get a cheap 100w Class-D with level control (to match level to the Aegir) for the bass, they’re good for that. (maybe your behringer pro-amp) and use your preamp as the master volume control. 
http://www.av2day.com/wp-content/uploads/2014/05/biamp1.jpg

Cheers George

read your model 2 manual on the recommendation to use identical transfer function amplifiers IF you vertically bi-amp
otherwise you can kiss time and phase goodbye.....