This is a brand-new spark plug:
After 16000 miles, all of them with piggyback tunings, using Shell V-power gas only ( 95.5 octane AKI = 100 octane RON ) my spark plugs look like this:
No visible wear, color grey, spark plugs of cylinder 5 + 6 don't look different ( cylinder 1-6 from left to right ). IMO I changed too early, but this is good to know.
Looks good to me.