That question will divide opinion. Some on here are far from impressed by iridium plugs and you have to question are they worth the extra cost. How many and what sort of miles do you do ? If you are not stressing the plug surely standard plugs make more sense. Andy
5k miles a year .... just thought that iridium plugs made for easier starting like they did on my aprilia rsv ... cost wise, not much difference
I have iridium plugs. The theoretical advantage is that they can cope with a larger gap and come set that way. This should make for a fatter spark, which should give better throttle response and fewer low-speed misfires, so it should also idle and pick up better. The other big advantage is that they are pretty much fit and forget and should last tens of thousands of miles untouched. It's all a little subjective but mine do seem to work as predicted and the engine never, ever stalls on its own.
I have NGK but on my 999 Testastretta engine, NGK plugs are a pain because the hex flats that the plug spanner fits on are further down towards the tip than the stock Champion plugs. This means that plug spanners tend to foul the tapered sides of the 'plug-hole' before they can fully tighten the plug. I had to file off the corners of my oem tool-kit plug-spanner to get it to work. I don't know how Denso compare in this respect
