You will need to seperate the crank case breather pipe from the turbo inlet. This feeds oil vapours and combustion blow-by back around into the intake (emissions regulations reducing oil fumes by not venting to atmos) . On mine I have removed the whole intake filter box assembly and replaced it with a simpler airfilter>MAF sensor>silicon pipe to turbo.
The oil recirc pipe feeds into a small seperator pot, where after a few weeks running a small amount of oil condesates back to liquid, the small second tube vents the excess gas downwards under the car.
changing the intake assembly saves alot of time on servicing later as things are easier to access, and quite a few Kgs.. mine also runs Very well
1.9 JTD M-Jet 16v 140ps.
Gas flowed head, Polished valves, Port matched manifolds, New Turbo.
JS-T primary Decat, MrZ full-bore Center Decat , Oil recirc tank, Big filter conversion.