battery disconnect.
Remove boost pipe, and TB.
Unclip wiring connectors for knock, lambda and err other one or remove bracket totally.
May have a strut on the back of the G40 manifold, remove this from under the car. loosen and remove the ISV pipes underneath and vacuum pipes.
Remove the inlet manifold bolts and stud nuts, withdraw manifold (may need to remove the oil pressure banjos on head if in way, (i forget if there are in way)).
Fitting is reverse of removal.
*Subject to misinformation* - It has been 4years since i did one.