Just serviced my beloved 2013 R56 JCW Mini.
It has 40, 446 miles 'on the clock' and the oil is changed every 12 months/5000 miles.
These Champion 12ZR-6SPP2-1 were dealer fitted in September 2017 at 19,602 miles.
Do these plugs give any indication, as to the condition of the engine?
I'm absolutely no expert, so any advice from you knowledgeable members, is greatly appreciated.