I like very much your work, just a little note, I think the leds on the sli could be better tuned, while driving they stay on all the time (except the central ones) with a f1 car like the lotus 72, you can tune the scale to represent only the upper section of the range in order to make them useful while driving the engine in a race, close to the upper range of the revs... I used
limits = 0,78,80,82,84,86,88,90,92,94,96,98