The coil is simply connected by two wires. So adjust your colors accordingly. So the Hi6 reads the two coil wires, and send it's own current back to the coil via two other wires. This is very much like adding a car stereo amplifier.
Many speed shops tend to simply cut off the factory terminals during installation of the unit.
The negative wire off the coil can be removed entirely. I would do this and save it. You have two choices. In other words, cut two pieces of wire. Twist two ends together and use an insulated female spade connector.