Battery ground wire and hot wire section

Nico, Do not use the frame as a ground, it will act as a high resistance fault and you will have trouble starting you lighting will be dim and you will have ground gremlins. I know, I did it once and had to re run my ground to fix the problem(s). Ground from the battery to to the engine, I use a bell housing bolt or a starter bolt as the connection point. Secondly, don't switch the ground as your security feed, it can easily be defeated (think about it). Switch the power lead, it's very difficult to defeat this configuration.