there is a wire gauze in the cam housing on the 8v engines, this can become blocked easily, and cause increased backpressure in the crank area. also the pipe you mention which comes out beside the dipstick and joins the head, that will be lined with yellow crap, clean it all.
Sorry to hi-jack this thread but which pipes exactly are we talking about here? My car's running a wee bit rough just now (i reckon its the leads) but i also want to check the breather pipes.
I need an idiots guide i'm afraid! I had a drip from the top of the pipe at the rear of the engine (it starts just below the 'turbo' cover and ends down the back of the engine somewhere), which pipe is this?!