Just something to keep in mind.

10 year old sports cars are not driven on sundays by little old ladies.
What looks cheap to purchase at the start could end up being potentially fairly expensive. I'd rather buy a $22,000 MY00 than a $16,000 MY96, more milage and more likely to fall over.

The $7000 saved could very easily be eaten up over the course of a year if the gearbox let go, the engine throws a leg out of bed, whatever.

Older WRX's also seem (this is a generalisation) harder to insure and more expensive.

I'm not saying all old WRX's should be avoided, but just keep in mind that any older sports car can start costing you a hell of a lot of money really fast, and perhaps it's not something for you if you're already stretching the budget for the initial purchase.

**edit:
http://www.perth-wrx.com/vb/showthread.php?t=6260

Can you find a MY96 cheaper than that?