A brief update. Today I eased the inlet manifold away from the head and looked at my inlet valves at 10,000 miles. I didn't take a photo, because acces is poor and it would look the same ar Marks. In fact the carbon deposits on mine are black and shiny, but not as thick. Realistically, because they are buried so far down in the head, cleaning in situ is inevitably difficult and time consuming. So for now it's back together. I decided to use a single port for the valve saver kit, because the manifold is quite a thin moulding, and so making four sealed ports is far harder than a single port just downstream of the throttle body. More on this to follow once installation is completed.


DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4