I full accept that the ride will be worse on 19s with a 235/35/19 tyre than a 225/40/18 due to the lower profile.
What I'm trying to understand is why people also report that handling 'is ruined' on 19s?
I would have thought there were a number of reasons why a move to 19s should have improved handling:
Good quality aftermarket 19" wheel will weigh less than an OEM Audi 18" = less unsprung weight
An 8.5Jx19 ET45 rim will give an overall wider stance than a standard wheel (without spacers)
A 235/35 has more rubber on the ground than a 225/40 - more grip (unless its snowing!)
235/35 has about 9% less height than a 225/40 - less roll in the tyre when cornering
However I'm told this is not the case and these factors combine to give a worse handling car?
Can anyone explain to me why?