I've read loads of bits saying that changing the setting on the octane plug will make a difference especially if using supr unleaded.
WHERE IS IT on the C20xe???
Will it affect mpg/emissions?
I've been told on my engine to set it to "A" does that mean it will be set to "B" as standard?
I've also been told there are different plug to fit. What should mine have and which ones are best?