I'm no expert either, but I have managed to flash my MY04 with success.
My steps went like this:
1. Buy the tactrix cable (
www.tactrix.com) from Colby.
2. Download & install Ecuflash
3. When the cable arrives, install its drivers. At this point you can use a realtime viewer (like Ecuexplorer by Tari racing) to view what kind of numbers you are currently making. Do some logging, have a passenger what what your car does in different gears under different throttle positions and the like.
Two paths from here: The more complicated route is to edit parameters on your own to what you feel like will result in a car that has a margin of safety and reasonable power gains. I'm just not knowledgeable to do that, and I don't have a tuner locally sooooooo....
I went the noob route. I downloaded a map.
XPT tuning offers free maps on osecuroms.org, and maps with a bit more tuning done to them for $25.00. I took the plunge on the $25.00 map, and am quite happy with my stage 2 wrx.
Then its flash time.
5. To flash, its going to vary on your year of ride. Mine required (MY04) a set of green connectors to be linked under the dash, and a jumper installed to pass voltage to the ECU. The jumper comes with the cable.
Here is where you need to do research:
www.scoobypedia.co.uk has step by steps on the actual flash process. Let me be clear this isn't something you can screw up. Your battery dies midflash, or your laptop dies midflash, you turn the key off midflash.. you fry the ECU. Thats it, no more ECU.
6. After its flashed, give it some break in time. Took me ~100 miles or so for the logs to show I was properly correcting and all that. Good luck, hoped this helped!
....
And if you fry anything using my amateur advice, tough.
