Not shure if it's just me BUT i think any rim smaller than 18''on a MK5 looks lost in the arches ?.
Im sticking a 245 profile tyre on it though, so its going to be pretty fat, with the car as low as I intend on running it, I think it should look ok.. For sure 17" is getting a little small, but it will make a huge difference to the performance, which is what mine is all about..