Some of the wagons are of the WRX variety, I own one. A Lot of guys like to play around with the motors in them. The stock engine is a dumbed down version of the one Subaru uses in the rally car. If you spend the money to put the rally parts on it you can easily get 500hp and about 400ft.lbs of torque.
My friend Matt manufactures and sells parts to hop up Subarus:
http://www.kstech.biz/Subaru owners go nuts on mods and mapping. The ECUs are apparently programmable out of the box.