Fully synthetic, its not the oil, every body gets oil in the pipe work hence the catch tank, the gunk is due to moisture from the air mixing with the oil vapour.
only notice smell if she's had a kickin and I'm sat at traffic or slow movin.
There are some good pictures here and description of fitting. Look at post 138 onwards.
I've got a Toyosports one that I'll be fitting this weekend.
Those are good picsNow where to get one of those metal T pipes...