I want to put mine in the left ac vent above head unit. My question is that I installed one a while back on my 04 cobra but where is the Tach switch located on the GT500's. On the other car it was on the passenger kick panel.
I wired mine to the rear pass side coil pack for the signal, works great, you can get a 12v source from the coil pack wire also. But I got my power from the pass side fuse box and a ground from next to the glove box. Pull the glove box out and you'll see a ground. Raptor site has some directions on it.
I just installed one and did the hook up in the instructions on the ECM, mainly because I installed WOT box at the same time I was going to have the three ECM plugs unwrapped anyway.
I just did this today...tapped into the wires at Ecu under the hood as stated in raptors instructions. Works mint. Mounted mine right in the center of the cluster where the temp and oil press factory gauges are. Looks great and you can see it clearly while looking straight ahead.
I don't think it matters where it's mounted it's brighter than the crazy bright. I had one about 3 years ago and loved it so much I got it again for the new ride. I set mine at 5500 in order to give myself enough time to change gears haha