Rs6 9 spoke Wheel fitment

[madcjd]

I have recently bought a 2001 D2 3.7 sport. I'm currently refurbing the original 7 spoke wheels.
In my garage, from my previous car, I have a set of immaculate genuine RS6 18" 9 spoke wheels. You can see where I'm going with this........
The offset of these wheels is 30 and the width of the rim is 8.5". The original A8 wheels have an offset of 48 (I think). So, if my calculations are correct, the rs6 rim will stick out 18mm (offset) + 6mm (half of rim difference), totalling 24mm. That's sounds a lot!
Any thoughts or concerns anyone?
Hope to stick on one in the next few days to see how it looks.
I've been trying to sell these wheels before - with no joy.......now, they might have a use