That looks really cool! I'd love to see how it looks once it's backlit!
Question-is the actual sweep of the old gauge the same as the sweep of the newer gauge? They look pretty similar, but looking at your odometer and stuff it looks like the newer face shifted numbers around a bit. Do this-check your MPH speed versus your km/h speed. That'll tell you if the sweep changed at all (and is thus not accurately telling you where the speed actually is). 40 km/h = 25 mph, 60 km/h = 37 mph, 80 km/h = 50 mph, 100 km/h = 62 mph, 120 km/h = 75 mph, and 140 km/h =87 mph.
If the sweep or the angles at which the needle versus the speed have changed, you might be reading off, especially at the extremes of the gauge's range.