As far as grip and performance...
Imho Treadwear is more important than size.
Check the treadwear rating on your tires.
VWs are light so they can run the grippy lower treadwear tires and still get decent life and improved grip.
example...A 165 with a softer 200 treadwear is going to out perform a 185 with harder 320 treadwear.
The old 145 fronts that many use last for years and never wear out the tread with a 300+ tread wear.
According to the tire rack website after 3 years the tire has lost 1/3 of its strength (rubber drys out) and you get less grip but still have full tread.
Amazes me someone builds a nice expensive car then runs dry rotted 10 year old tires on it?
Each tire has a 4 digit number that represents the week and year your tire was made.
The rubber on the tires drys out after 5 to 7 years even if never used.
Ideally in 3 years with a lower treadwear you have experianced max grip, tread is worn down and the rubber is starting to dry rot.
Then its time for new tires, and you'll know you have got the most perfomance from your tires.