I managed to get my new wheels and winter tires swapped onto the Jetta last night before the snow came, and man what a difference:
For reference, it used to look like this:
My spacer choices (10mm front, 20mm rear) we’re dead on balls perfect with the 17x8 et48 wheels. The track is the same front and rear because Mk4s are narrower in the back from the factory, and my spacing gets them right out to the lip of the wheel arch. Maybe a tiny bit inside, but not outside which is perfect.