Took my girls 2016 Mini apart over the weekend to clean the valves and install a CC. I was surprised to say the least at the lack of carbon build up on a direct injected motor. I then noticed the injectors are located on top of the motor by the spark plugs and angled towards the intake valves. You can see a small spot on the back of the valve stem but manifold and IC were oil free. The car has 15000 miles on it and is tuned with a JB4.