rich, lean or stoich?!

Hard to tell from the pics.



This is how a good spark plug should look.
The colour (Grey-tan to white) shows that the engine is running well.



Fouled with carbon deposits.

This can be a common thing on hard driven cars. It indicates a rich
fuel mixture, weak ignition or wrong plug (too cold).

Think about a tune-up or mini-service consisting of new
air filter, ignition leads, carb clean etc.