Do not waste your money on all those so call grounding wires. Your car body itself is the ground at all times. Just take a look at the battery terminal. The negative terminal is connected to the body which serves at the ground for all the electronics in the car. A good ground means that the resistance must be zero between the negative terminal of devices and car body which in all cases is already zero unless there is some contact problem. So do you think that by installing the so call grounding wires would improvement ? Answer is no.
