The other day I dropped my car off at a European specialist shop, and while I was there, a technician was working in the engine bay of a Mk7 Golf R, cleaning out carbon deposits off the intake valves.

If you think about it, there are things about your car that just don’t make sense. You’ve been told that more air is a good thing for power, that a cold air intake, more scoops, more vents, etc, are a ...