The reasons the plug companies are going with R plugs across the line is bc the new computer cars are effected by stray RF interferance, whereas the older ones only concern was radio interference. [ spark frequency transmission].

I did some experimenting on an older classis IL 6 MFI chassis I own by eliminating the plug connector resistors on the wire ends and going with the newer R replacement plugs
[ standard Bosch R Coppers].. I found this to work well , but I then also found that the
Bp5es Copper non resistor worked even better and I still had no RF , mainly b/c you still have the R factor on the rotor/cap carbon and I also have a New JVC sound system...so, who knows.
I love NGK plugs, specially the last few years when I had plenty of trouble with the India Bosch..

Something to consider.
What I do not recommend on the older ignition sistems [ and Waste Spark ones] , is to use R plugs topped off with A Resistor Plug connector.........

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A Dalton