Craig.
Handling Mods: Tein superstreet coilovers - whiteline ARB/droplinks/Ant-Lift Kit
Power Mods: VF38 Turbo/Sports Cat/Uprated Oil pump/Fuel pump/Plugs/Panel filter
Since I am running a 2.5, I get 340BHP and 400 ft/lbs torque. Woes to date include broken piston and broken gearbox. The reason the piston broke was because the 2.5s run tighter in the bore, so it looks like the much higher temps generated during track use caused the piston to get nicked in the bore. I now have uprated pistons and racing shells. Since you are running the 2.0 in your WRX you should be ok, espeically if you are not going to be running it on track. With the gearbox, you should also be OK with that, especially if you are not running on track and becasue the 2.0 doesn't provide as much torque as the 2.5 - torque is the real killer where the gearbox is concerned. The WRX box is not nearly as strong as the STi 6-speeders.
Hope that helps!