I went with the Autometer ultralite (silver face) boost guage in the dash. I wanted to have a blue light. well I had a few options. put a blue bulb in and have it burn out (burn the color off), try to find a blue "condom"or, what I went with was a Blue LED. all you need is an LED, a resistor and the stock bulb shroud, the part that twists into the guage itself. all you have to do is remove the bulb and wires from the housing, go to radio shack and buy a 12V led, a 330 ohm resistor and some solder. solder the resistor to the longer wire from the led and stick it into the housing, it will be loose but you can fill the void with hot glue. then just hook it up like the origional would be. the side with the resistor will be your positive side.I have no pics, wish I would have taken some now :
Hope I helped
Mad Mike