I was on the Audi bbs, hey they have AWD don't they, and came across this link about a new shop that is opening called Curry's Auto Service in Sterling VA, that has an AWD dyno. The seem to cater more to the Audi/BMW people, but I am sure that they would have fun seeing what a WRX can do on the dyno:

Curry's Auto Service (http://www.quattroclubusa.org/r/potomac/events/currys_tech.html)

Lovejoy

there's another opening up at a place called AWE Tuning in PA.

check out their site AWE Tuning (http://www.awetuning.com)