Thanks Lexman8
I tried tire size.com and got -0.3%
The circumference really is not an issue 90mph reading the car will be doing 89.7 so I think that's all good
My worry was with the pilot assist stuff as I do a lot of long European driving and I feel the pilot assist will get used a lot and I want it all to be safe.
If I swap the wheels just don't want to have to pay twice a year and have to deal with all the booking in and waiting at the dealer.
Any one go from 22 to 20 or any other opinions.