I am trying to find a used set but am having a hard time verifying fitment. Does anyone have the wheel specs that fit an R56 Coupe?

 

Where are you?
There are many sets on Craig'sList Massachusetts & New Hampshire.
& VT & ME

 

I’m in Notherstern,PA. There is a set in Binghamton, NY which is not that far but they are 205 55 17s. Again, I am not sure of the off sets and what would fit. MA,NH and VT are a bit too far and I think shipping would make them too expensive.

Do you know if the 205 55 17s would fit?

 

It snows more in northern New England so there are more available!
I'd just call/email possible vendors & ask what car they were used on.
Do you need 4 or 5-lug? 12 or 14mm bolts?
I'd go for a smaller rim & a higher profile tire if you can - much better in snow.
I have 185/65 x 15 on my early R53 = the same overall diameter as 205/45 x 17 summer tires.
You can limit CL searches to within xx miles of your zip-code if that helps.

 

I believe your stock tire size is 205/45-17 having an outside diameter is 24.264” vs the 205/55-17 having an outside diameter of 25.877”! This is way larger and rubbing would probably be in many places.

I have 15 years of owning my MINI and 29 years designing extrudes for the tire companies.....and my wife has 25 years developing compounds for Bridgestone America......