Installed my Greddy Multi-D/A gauge this weekend. The install into the vent pod was super easy. The gauge is 62mm so what I did was just use some industrial strength velco on the two flat side pieces and the gauge. It keeps everything completely snug.
Wired up the constant/ign/illumination separately since the gauge has a peak/hold function and also a shutdown sequence which requires the constant 12v. Having the 12v Illumination hooked up dims the gauge when the lights are on. Only gripe I have is the IR remote which comes with it doesn't work all that great.
Here is a crappy picture of it with the "blue" LED backlight.
