I just did my spark plugs yesterday, and they were the factory Denso plugs, and still in great shape after 25k+ miles.I tried some Iridiums in my 99 and it seemed to lack bite. Went back to standard NGK CR8E . Spark plugs are not just a spark but are also designed for the best Dwell-Angle when igniting. I also still have the Factory fitted ," Denso " plugs that I took out @ 26k miles and are still serviceable. I keep them in a pouch as spares under my rear seat.
Tip: If you have the Factory Tool-kit hinged plug spanner/wrench you can use it's back-end box 10mm spanner to remove the 3 Rad bolts and push the rad forward to get to the front plug if you take off the Horn bracket without having to drain the coolant. I keep a small piece of cardboard with some double sided tape under my seat to protect my knuckles and rad when messing with the front plug.
I left my Horn bracket off and moved my custom horn,
More info here on checking Spark plug caps,
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