Marc:
My point being you are less likely to get a non-resistor plug "by mistake" for a car which requires resistor plugs as opposed to being given resistor plugs for an MB, which happens quite often when trying out an "exotic" spark plug.
Gilly

__________________
Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)