OK, so I did some homework last night. Reletive to the OEM 19" wheels on the F10 M5, if I swapped in my E63 M6 wheels (see widths / offsets in my original post) it would result in the follwoing changes:
Front wheels - 26mm additional interior clearance (inner lip farther from the body) and the outside of the wheels will be 14mm farther out
Rear wheels - 23mm additional interior clearance (inner lip farther from the body) and the outside of the wheels will be 11mm farther out
Based on these results, it seems that the wheels will fit. However, if I take the average of these two numbers as an approximation for the change in the center of mass for the wheel swap, it results in 20mm outward shift on the fronts and 17mm outward shift on the rears. Now I know plenty of people that have run 12mm and 15mm spacers on their E60 M5s with no adverse effects, but what are people's thoughts about pushing the wheels out 17mm to 20mm? Obviously it will impact handeling - but this is for my winter tire set when I will not be pushing the car as hard as I would on the summer wheels. Any thoughts about the additional stress on the suspension components and potential for damage?
Thanks again for any advice, comments or suggestions.