I've been to this place before, not for a dyno run though. It's a bit tight of a spot for parking if you wanna bring more than 5 cars, it's about a mile from where i work.
There's another good dyno place, where i had my tune done, in Sterling. It's close to Worcester, ESP. I think it's $100 for 3 pulls in AWD mode (that's how they run our cars there) but might be cheaper if we have like 5 or more cars.
Here's the info:
http://enhancedstreetperformance.com/index.php?option=com_content&view=article&id=7&Itemid=6
Just throwing it out there.