Marc, the wiring looks good so far and most of those wires won't be used, so don't let the quantity of wires worry you. However, I'd suggest keeping the grounds from the EFI electronics separate from other grounds if possible. So, I wouldn't connect lighting grounds to that same ground point as the 7 black wires, and I wouldn't connect any of the ECU grounds directly to the frame. You should have a single clean power and ground wire coming from the battery to run the EFI box, and use a separate power and ground wire from the battery to run the other electrical devices like lights, electric fans or water pump, etc. Even though from a DC perspective this is exactly the same thing, from a signal noise perspective it is not. Electrical noise is the enemy here. Also, I would suggest a big bypass capacitor up near the EFI box. MSD makes some for their ignition boxes that work quite well for that application. So, I'd suggest from your ECU relay, run a big wire to a bypass capacitor. Then run a separate big wire (#10) from the battery negative up to the capacitor. From there, make all the power and ground connections for the EFI system at the terminals of the bypass capacitor. This includes sensor power and ground connections, for the crank and cam sensor for example. Don't connect any other power, or any other grounds, to that capacitor. That will ensure the cleanest power supply for the ECU.