If you tend to hit a lot of potholes then I would recommend that you steer clear of the 17" Audi A2 Sport 9 spoke alloys.
Two reasons, firstly they are very heavy wheels (VERY). so the unsprung weight can add to the bump you will feel when you hit a pot hole.
Worse still the same wheels are VERY soft and suffer from buckles, especially on the inner rim.
As for the 17" compared to 16", I am probably going to sound like a broken record here, but if you hit a pot hole, whatever wheels you have on it will be a really horrible bang. Dropping to 16" will give you half an inch more side wall and I am not sure how you would feel less of a bang from a pot hole ( every pot hole is different and you hit them at different speeds and different angles and so there is no scientific logic that would mean that half an inch more tyre wall would make a difference when you hit a pot hole.
Better tyres, lighter wheels, correct tyre pressures, quality tyres, decent shock absorbers and correct springs all affect the bang you will feel.
Much more than half an inch of rubber. One other thing to consider is that if you currently have rattles and squeaks from various interior parts and loose items in the cubby hole and various trays / in the boot, that can REALLY make the effect of hitting that hole just sound worse too.
I am just trying to help people get the best ride from their A2, the last thing I would do is to drop an inch or two in wheel size, I would get everything else mentioned above right first. Dropping the wheel size will of course make a difference but my point is that in dropping a wheel size you will be fitting / using different tyres and pressures, so there is no actual comparison you can make, it is comparing apples and pears?
Dropping a wheel size will slightly soften the ride at the expense of slightly poorer cornering and steering response (in an accident you WANT to have as good a steering response as possible to miss hitting someone.
So if you feel that half an inch or one inch of difference in the tyre wall softens the ride noticeably, then that same logic applies to the steering response and cornering, and you will be affecting steering response and cornering grip (at NORMAL speeds, these are not race cars) by the same amount, scientifically!
There is a reason why Supercars have ultra low profile tyres, that is because they DO improve handling and steering response, that is an accepted fact. I am not saying that A2s are supercars (but they are "super" cars
) I am just trying to illustrate the logic.
I will try to make this my final statement on the wheel size debate, I don't want to bore or alienate people, I am just trying to add my views.
Rant over
Steve B