2007 S3 problems - any help appreciated -

[SSS3]

who paid for the work to be done then if it,s under warrenty and someone else repairs it

Warranty - mechanical failure in this case had nothing to do with any of the changes made.

There might be another problem lurking here tho - the oil on the old Airflow sensor could have been blowback due to a faulty valve.

But we'll keep an eye on it :>