Which plugs are best for performance?

Can't think of the current flow like as a regular circuit. This is a charge with a driving voltage that diminishes over time. It jumps the gap from the rotor tip to the terminal like lightning and then again at the spark plug tip. So in this situation a short section of resistance doesn't change the energy so much as its form (voltage and current over time). Obviously any real high resistance will be problem, just like too large of gap.

Most distributor caps now are vented to help reduce the build up of ozone and chance of cross fire.