Yeah my impression is it just got missed - both in qscript which can't set the clutch control's position, and in the system variable, which has only signals from the clutch. Too bad, with access to a real clutch you could simulate the model T's clutch pedals (left for low/high forward gears, middle for reverse) perfectly.
The scripted gear changes seem to work ok on my Racer 0.9.0RC5d but not Harey's, or maybe they're actually not working for me but I just don't have any gear shift sounds to tell me. I did end up in the weird situation where shifting using the actual buttons would get the car stuck in 3rd gear and then be unable to change back, didn't follow the logic on that.
No engine support for track lighting, I think it'd be possible using custom shaders but they'd need to be used on every material in the track & car, and all import the same lighting resource (some sort of texture map showing what the light sources are)
You can sorta fake it for the car itself using the environment map to produce ambient light, but it doesn't blur out wide enough to look great.