Do your self a favor mate and give Amcap a call with your vin no and go collect your genuine radiator for $303.

13/39 Pilbara Street Welshpool WA 6106
(08) 9351 6666

Replaced the radiator on my brothers sti last week. They've come down in price and are a good radiator for the money.
On top add the following and you're good for a while

Genuine coolant
Thermostat while you are replacing the radiator. You can pick up a thermostat for pretty cheap from Subaru with a seal
Engine flush while you have the chance
Bleed/burp the cooling system

If you can do it all your self it will be a bonus on your behalf as you will save on labor if anyone else was to do it