Came across quite the setup on ebay and it seems these guys have quite a few options... But 6MT w/ brembo's, diff, etc for $4k... I thought it was tempting, but I don't know much...
http://www.ebay.com/itm/Wrx-STI-6-Speed-Transmission-TY856WB1CA-Differential-STI-Brembo-Brake-5x100-STI-/251396923944?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a886ca228&vxp=mtr