Hi Tintin
I have not done this job myself, but this is a simplified version of the Turbo removal procedure from eLEARN for the earlier vehicles (Euro 4). The engine does not need to be removed, but you need to be able to work from both above and below. I would recommend removing the bonnet (hood) cover for better access.
From above: Remove heating / AC air inlet ducting (to give room for access)
From above: Remove rigid air pipe between Intercooler and Turbo
From below: Remove intermediate exhaust pipe with hose section
From below: Remove exhaust Catalytic pre-converter and Lambda sensor
From below: Remove Oil return pipe from Turbo
From above: Remove Oil delivery pipe from engine end, loosen air hose clip
From above: Remove 3 nuts from Turbo/exhaust manifold and loosen fourth nut
From below: Remove Turbo air inlet hose
From below: Remove 4th nut from Turbo and remove, complete with short oil supply pipe