Bottom line: IMO, yes you need an oil catch can, and you need one sooner than later. Even with only 9,500 miles on my Gen 4 when I bought it, I still has an nice oil glaze on the inside of my intake manifold, and I also had the nice oil snail trails coming out of both throttle bodies from too much oil being pulled in. The oil catch can I'm running has helped to pretty much eliminate that issue entirely. If there is oil getting by, it ain't much.