The trouble is,whilst pretty much anything is do-able,it comes down to time and cost.
As has already been said,bolting the manifold and turbo onto the engine is no big deal,but the pipework,diverter,and fuelling all need different parts,and then of course you need it mapped to deal with the bigger turbo and airflow.
And...if you do all of that and turn the boost up,you may need to consider engine internals,as the S3 rods are uprated by comparison with the 2.0TFSi.