detonation will sort of look like little welding splatters, or melted pits. Your plugs look clean to me, and the heat pattern looks pretty good too. I can't explain this very well, so I would keep asking the Bro's here....and the Sisters. And research all you can on the 'net. It's fairly simple on a regular car, and hard to get too picky, as the conditions change so much(traffic, highway, idling, cold, hot....)