Hopefully this won't devolve into a "performance" filter flameout, but have recently fitted an oiled 3-layer foam filter to my tuned GTI. It's an ITG manufactured filter and is HUGE. Not a drop-in and has much more surface area than the OE (actually pulled apart all the pleats in one and measured it). I'm not really concerned with the flow as the OE box and snorkel does pretty well. Its more of the overall design coupled with some other intake components that gives me a noticible improvement in spool and response. I am NOT one of those that is concerned with intake sound and this set-up is almost as quiet as OE Where my concern lies is with filtration. I understand that the OE paper is best but would an oiled foam be THAT bad? I put about 7-8K a year on the car and it take forever for it to cause long term damage if it filters poorly. Haven't had a chance to do a UOA yet as it was fitted so recently. I guess I'm asking a subjective question, but curious if anyone has solid experience with oiled foam or any kind of test results with them. Scoured the 'net and haven't found anything really definitive.