I bought my first mk6 with 17's and changed to 18's pretty soon after.
No real difference in ride quality and I had several different sets of 18's over the time I had the car (seven sets I think?!!) using different brands of tyres.
Then I went to 19" BBS and again, no real loss of ride quality from the 18's.
Pick up a second hand set of 19s. Then can always sell them for roughly same money if you don't like them.
I recently went from 19s (Glendales) to 18s (Monza 2 Shadows). The ride is not massively differently, and certainly wasn't bad on the 19s. Having had both, my view is pick the wheels you prefer the look of as the ride is not massively different.
Why the change from the rather nice and rare Glendales to the Monza's Nor?
I'd have loved a set of Glendales on mine but they weren't an option at the time and you never saw second hand sets come up for sale.
