My fiancée requested the wrong size tires... how bad is this?

[Spongeworthy]

My 2004 S4 needed new tires after a flat, so my fiancée called around to find someone that had them in stock or could order four new 235/40 18 tires after she read the number from the inside door as the required tire size. She didn't realize the wheels were not factory and require 245/40 18 tires.

I'm back in country now (traveled last month for work) and quickly noticed the problem when I saw that the Audi seemed much lower. Thankfully the car had only been driven 94 miles since tire installation and alignment.

Before driving the S4 to the Goodyear we purchased the tires from, I need to know the likelihood they might exchange them for the correct size. While it's true my fiancée did request the wrong size, didn't they notice upon installation that they were not the same size as the old tires, moreover they look much lower?
I know the tires aren't often requested there at either of those sizes, but I really hate to pay for TWO new sets of tires.

Also, just how bad is it to drive on these 235/40 18 tires? I was calculating the difference in height as 235/40 = 5.875 and 245/40 = 6.125. So is 0.25 mm the difference in height from what the radius to the ground used to be/ should be, and what it is now?

Cheers and thanks

[inafogg]

with 94 miles on new tires i'd dought they will exchange them
as far as the difference in height i dont think you will notice much
in driving or handling. as for everything else speedo ect.i think you
will be ok.
other opinions may say differently

[MagicRat]

Spongeworthy............... I used that as my subtitle for a while. Funny.

So why do your aftermarket rims "require" 245 tires?

Unless they are significantly wider than stock, I see no harm in returning to the tire size that Audi intended for the car, (presuming that Audi actually did indicate the 235 tire is the correct original size)