They were all burnt round the tip and burnt round the ends of the ceramics, they wernt in good nic at all RIK they were pretty poor, plus engine wasnt running as smooth as it should, after the new plugs the engine was far smoother and the response from the throttle was brilliant!
yer cracking ceramic is well easy, because they are realy brittle, but ceramics are the most heat resistant materials available, someone said the ceramics were burnt, wich is realy hard to do