Here's another "will this fit" question about UEL headers for an 06 model. See link below.
Link:
http://www.ebay.com/itm/STAINLESS-STEEL-EXHAUST-HEADER-MANIFOLD-02-07-SUBARU-IMPREZA-WRX-STI-2PC-EJ25-/180852568047?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3ASubaru%7CYear%3A2006&hash=item2a1ba72fef&vxp=mtr