More specifically for the WRX,
With the stock bits, you're not going to have much room for adjustment, but here's what to try for:
Camber:
The front camber should be set as far negative as they can get it, which will be in the -1.3deg range IIRC. If they can weasle -1.5deg out of it, that's great. Rear camber is not adjustable w/o new top hats or eccentric bolts. Mine were at -1.2 and -1.3 degrees, which honestly is too much, it's wearing the insides of my rear tires too quickly.
Castor:
I don't believe castor is adjustable, but they can tell you what your at. You'll want a much as is possible with the stock setup, but again, I don't think they can change it. This is one of the nice things about the ALK... more castor, but alas, not on an STX car. As Austin said, positive castor is a good thing. It'll be a bit stiffer to steer, but as you turn the wheel, your camber goes more negative, which helps the tire to bite as the car rolls.
Toe:
Up front, zero is the best on the WRX IMO. Rear toe is more of a matter of opinion. I had mine set just a touch toe out in the rear, the idea is that in a hard turn, most the car's weight is on the outside tires, so if the rear outside tire is toe'd out, it will act a little like 4-wheel steering and should help the car rotate. However, this will increase rear tire wear (esp. since the rears are over-cambered).
Here's a basic alignment for the WRX:
Code:
WRX Agressive Street Alignment:
FRONT
LEFT RIGHT
Camber -1.5deg -1.5deg
Castor +5.0deg +5.0deg
Toe +0.0deg +0.0deg
REAR
LEFT RIGHT
Camber -0.5deg -0.5deg
Toe +0.0deg +0.0deg
--------
WRX Track Alignment:
FRONT
LEFT RIGHT
Camber -3.5deg -3.5deg
Castor +6.0deg +6.0deg
Toe +0.0deg +0.0deg
REAR
LEFT RIGHT
Camber -1.0deg -1.0deg
Toe +0.5deg +0.5deg
--------
Realistically Attainable
Stock WRX Alignment:
FRONT
LEFT RIGHT
Camber -1.2deg -1.2deg
Castor +4.0deg +4.0deg
Toe +0.0deg +0.0deg
REAR
LEFT RIGHT
Camber -1.2deg -1.2deg
Toe +0.2deg +0.2deg
Of course, I'm not an alignment guru, this is just what I've gathered from reading NASIOC, etc. and my experience trying to align my own car for Autocross. I'll bet Austin and Phil will have some insight on these figures, since they both have more racing/setup experience than me.