Take off your cluster binnacle, remove the 4 7mm bolt/screws holding the cluster in, then shine a light into the cavity towards the right... if your car's already wired you'll see a small 8-wire plug taped down, near the cluster pigtail! Also, check the pigtail going to the centre console from the dash; if it's wired for HUD, it should have 9 wires, not 4 (the console sub-harness of the non-HUD models will only have 4: 12+, ground, illumination, and traction control. The HUD controller adds 5 more...). I have an earlier 2004 GT1 (built January 2004) that wasn't pre-wired and I had to patch into the stock dash harness!
