I have wondered about non resistor spark plugs for several years. Whether they could be used, what problems they could cause (if any), how big of a benefit there would be, etc. So I did a crude experiment where I modded a spark plug to a non resistor to see if the spark was stronger. Basically what I did is I twisted the top terminal off, drilled the resistor out, put a 1/2 inch long piece of 12 gauge wire in the ceramic to replace the resistor, and put the top back on. I then removed 2 coils from the engine, put a modded plug in 1 and a stock plug in the other, started the engine, and observed the spark.
What I noticed was that the spark produced by the modded plug was significantly stronger than the spark produced by the stock plug. I swapped the coils around to see if maybe one coil was stronger than the other, but the result was the same: The plug without the resistor produces a stronger spark. This makes since because by definition, a resistor reduces the voltage and current available to produce a spark. Here is a video of the test I did.
Just for the heck of it, I put the modded plug in and drove it around for a month. No problems. The engine still ran great, and there was no interference with the radio or any of the car's electronics.
I then took it a step further and decided to get a set of non resistor spark plugs. I would have modded the other 3, but modding 1 plug took over an hour and I didn't have time or patience to do another 3.
However, finding non resistor spark plugs for my car proved to be quite difficult. I looked at NGK racing plugs, but I couldn't find one in the heat range I needed, so I looked at Nology spark plugs. I found that their D4YS spark plug was what I needed because it was the correct heat range and it was physically the same as the OEM spark plugs. Same size, same crush washer, same threads, etc, the only difference is that they have a silver tip and no resistor.
So I ordered a set of Nology D4YS Silver non resistor spark plugs, which cost me about $40 shipped. Once they arrived, I gapped them to OEM spec, installed them, and went for a drive. The car runs great! No problems whatsoever. The radio still works fine, all the electronics seem happy, and the engine runs smoothly. So I guess if there is any interference from these spark plugs nothing cares, which makes me wonder why they even use them. Maybe just because they are cheaper or some kind of FCC regulations or something?[\