I'm glad this post came up. About a month ago I installed an aFe Magnum Force intake with Proguard7 filter and filter sock. Then this past week I installed the afe Torque Tube. While I was installing the T-Tube I ran my finger around the inside of the turbo and it came out dirty. At first I guessed the aFe was the culprit but the filter only has about 500 miles of use on it. I then began to wonder if the factory air box or filter was the guilty.
Anyway, after reading the above I feel safe that the aFe Pro7 was not the cause but I will still check the turbo after 5,000 miles of use just to verify.
The kicker is DC say's that we should not use these "aftermarket" filters because they do not filter well. Maybe they should check their own design.
Also, FWIW my stock air box and piping appeared to be be assembled properly and everything was tight. Furthermore, the stock paper filter had under 5,000 miles on it and did not appear to be abnormally dirty like others have noticed.