Went for the pierberg maf off the 320cdi merc and what a difference. Number 1 it's reliable (touch wood) it's smoother, and more responsive.

If the management light doesent surface and it doesent hesitate then I think it's sorted the issue.

Incase anyone needs a maf anytime soon I'd reccomend this. Used the maf on my old passats as it solved the issue with Bosch ones breaking all the time on them too.

Fingers crossed I can start enjoying the car now.

Mpg improved and smoke seems better. Could be the case that the turbo is noisy anyway and I've fixed boost leaks or potential ones by doing what I've done.

Keep us updated with how it runs.

250 miles since Monday and still pulling strong.

 

did have the management light on earlier but I don't know whether that was an electrical fault as the car went a bit funny this morning for some reason. no lights, no radio, no reads from lambdas etc. cleared fault now though so fingers crossed. car didn't perform any different or smoke any more, light just came on unexpectedly