i have no clue, i dont smoke at all under boost, at all. The car is running great, better than ever too, very strong, so i dont know where the problem could be coming from.
i also found oil vapor in the intercooler piping that connected to my intake mani.
Oil Vapor in Combustion Chamber
-----
Positive Crankcase Ventilation System
Bad Piston Rings
Boosting When the motor is cold
There is always going to be some... but if your spacer was "dripping" oil I would be worried. Since you mention it was only "residue", I wouldn't worry about it.
The SRT had a bad case of oil getting into the Turbo Pipes via the PCV.
To the point it would be a tablespoon or two of oil if you were to drop the intercooler cold side pipe.
To solve it, you could simply put an upgraded check valve inline that would hold up better to the higher boost issues.
I haven't sat down and looked at the 2.0T FSI Motor Specs... so I can't really comment on a fix.
I need to take a look at my wifes GTI and see if she has any "residue issues" with the Forge Spacer. She's had it installed for almost 3K miles now.
I think she is due for another oil change also.