go update:

I am going for trailtech voyager, it measure coolant temperature (it own sensor), rpm from spark plug.
Whats doable is gear indicator (dont need it now)

Question remains...:
how to measure fuel level (at least reserve?) i just had tank off, tried to mesure those 4 wires, but wasnt able to get to know how does they work. Anybody did something similar? Any help?