Power and ground

The problem with chassis/ body grounding is "now." "Now" we have lots of sensitive electronics, and you can get into "ground loops" which can cause interesting problems. Unfortunately, tho, many of the electronics themselves are not properly set up to deal with this.......stereo/ cb/ radio equipment, etc.

A "single point ground" like "think (wood, glass) boats" where you have NO ground, just a positive and negative terminal

If you have a fairly conventional "simple" car with just lights, ignition, etc, you are pretty safe. You get into EFI, data loggers, and other electronics, it gets more difficult

MSD has/ did have an article on interference. It is possible for example, for the spark produced by an MSD to re-trigger it's own unit, creating false spark timing. This high powered spark can affect other "stuff" like the voltage regulator!!!