Radial Mount Calipers

Not that the brakes on the X aren't good enough on their own, thoughts on converting to a radial mount 4 piston caliper? has anyone considered or already done?

Unless you replace the fork with ones that are for radial mount calipers, you won't gain anything. The advantage of radial mount calipers it the stiffness of their mounting relative to the direction of the brake force. To mount a radial caliper to a WRX, you would need an adapter bracket that still would mount to the fork int he tradition manner, negating any positive effect.