I went from 17x7.5 +51 to 19x8.5 +47, here in Greece base gti 245 comes with 17" as standard
In low speed driving only difference i noticed is louder bangs over potholes speedbumps etc,
but above 65-70mph i am moving side to side on seat over bad road with uneven surface, the difference is very noticeable
The steering is more nervous when speeding in bad roads with cracked asphalt and mpg also dropped but that might be insignificant!