My friend Scott has an 04 wrx running just a little more power than stock and has a stock clutch and a F1 racing flywheel and he loves it! Just a little different when taking off compared to using a stock flywheel but I would get the light weight flywheel since you will be in there.
I would stay away from the exedy stage 1 and take a look into the SouthBend Clutches in the parts review section on here. They have a stage 1 hd for the 2.0L that would suite you with what you are looking for.
Just a FYI, the F1 racing clutches suck, but their lightened flywheels are good. I also have a F1 racing flywheel in my car and love it!
This F1 flywheel http://www.ebay.com/itm/F1-RACING-CH...85ffee&vxp=mtr
Then the Southbend clutch for the 2.0L http://www.dxdracingclutches.com/html/wrx_impreza.html
which is the first one on the list under 02-05 wrx part # KSB03-HD
Also, what power mods have you done so far? How do you drive during the week? Hope this info helps ya out