Welcome to the Subie family!!

Also,

1. Leave the BOV on it. They normally start leaking once you run 19psi+ for long periods of time but the car will not ever run right if you put a 100% atmosphere bov on it. If you yank the intake silencer out of the passenger's side fender and put a catless downpipe on you'll be able to hear the BOV much more.

2. Dont go with an HKS downpipe, its the ****tiest design on the market. I recommend Titek for an affordable dp that fits properly.

3. DP and a 3" exhaust will give you nasty boost creep so you'll need a tune to control the boost. Either get an AP and use a terrible off-the-shelf map, use the AP and budget for a Protune, or get an OpenECU tune. For a stock-ish car I highly recommend Scott Siegel at Topspeed for a tune.

What color are the Tein springs? They make some that are barely stiffer than stock STI springs and some that are way softer and designed for WRX shocks.
^^^I echo all of this. If the springs are S-Techs, I would almost reccommend (sp?) getting a set of stock sti springs and budgeting for a good, quality suspension setup in the future. Tein springs are kind of terrible (when compared to subaru's stock pieces anyway)...their coilovers rock though..go figure. An STI deserves some awesome suspension parts. I would say Whiteline, Cobb, and H&R are good names to know for when you make more upgrades.

Other than that, she's hot man! Enjoy her!