I just thought I'd share some interesting information I've found while researching gauges to fit in my dash.
As you would probably all know the correct size for the Coupe style 3 hole dash is 3 3/8".
Most of the gauge makers make this size. The hardest bit is finding metric gauges (which I guess isn't essential considering a lot of our cars originally came wth MPH speedos).
I've fallen in love with the Autometer "American Muscle" style gauge which has only just become available in metric-

There is also a matching tacho that also looks great-

Just today I was doing a bit more looking around and found these guys-
Speed Hut Custom GaugesThey fully custom make all of their gauges so you can choose the entire design on the gauge right down to the text style and needle colour! The gauge I've linked to is a GPS speedo so you don't even need to connect it to your transmission to get your speed. It even logs your quarter mile time, 0-100kms time, elevation plus heaps more. Looks awesome!
Anyway, just thought I'd share that info for anyone who's looking at gauges. Let me know if you have any other questions!