It's perfect for dirt, 4x and even freeride. Street is still pretty good, but it's not 100% street. As it sits right now, in this picture, it weighs 28 lbs. The frame is only 6 lbs, so it's pretty light! Easiest thing in the world to throw around for me.
I'm not sure about the size, but duncon can hook you up. I'm 5'8, and I'm pretty sure this one is the small/medium. The wheelbase is pretty short, but just long enough to be good for freeriding and rougher stuff. The chainstays are a little long, but you never notice it, and it manuals like a dream!
http://www.highintensitybikeshop.com/images/uploads/Hayes%20Rear%206%20adapter.JPG
or like this
http://di1.shopping.com/images1/pi/21/8f/36/77768801-300x300-0-0_A2z+Mountain+Bike+Disc+Brake+Post+Mount+Adaptor+Pm.jpg