"Typical hookers and blow comment"
For the 5-10k, you are actually better off getting an STI. You'll increase HP by 70hp and have a better transmission, brakes, (and other things).
If you are going to keep the car, do the timing belt and all 100k maintenance. Get a turboback of your choice (any downpipe + nice sounding catback). Stage 2 OTS tune for now. $2000ish between that stuff, including the timing belt change.
Upgrade the suspension and brakes. Rear swaybar, struts and springs, pads and rotors. $1000 total.
New tires for $500-1000, depending on selection and if you want new wheels... some more $$$ for that. $1500 tops.
You're looking at for $4500, you can have a reliable daily driver that's decently aggressive for the street. All of the parts can be installed yourself too.
... I do see your point with not wanting to upgrade to the STI. Used WRX/STI that are in good shape are hard to come by. If you have a good one, sometimes it's better to keep it.