It's oil coming from the breather. Also known as the CCV or crankcase ventilation. Gases/fumes from the engine are not vented overboard. They are rerouted to the turbo intake and seem to collect at or around the intercooler tubes & boots. It seems to bug a lot of PSD owners. I just clean mine off when I wash down the engine with hot water. The hot water dissolves most, if not all traces of dirt/oil. It works for me.
Biggest issue is that all that residue is going into your intercooler too. Many people have reported that they have had a significant amount of oil in their intercooler.
Do the CCV re-route and you won't have oil running through your intake system anymore.
If they do an inspection then yes. But it's also very easy to put back when you have to go in. It's only a plug in the intake, where the hose from the valve cover comes in and a longer piece of hose to re-route it. All you'd have to do is pull out the plug, unhook the long hose and put the stocker back on.
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