The rolling diameter won't be much different. Regarding the wheel width/offset and tire width, you comp wheels are 19x9 +31. These VMR's will be about 3mm more aggressive (9mm further out from offset plus 6mm sunk in due to narrower width equals 3mm more aggressive).
If you are running the recommended 245 width summer tire on your ZCP wheels, the new tires will be 10 mm narrower meaning that the shoulder of the tire will be sunken in or stretched by 5mm.
Combine this 5mm sunken in (tire) with 3mm pushed out from above (wheel) and you end up 2mm sunken in, virtually no change. Of course, tire widths are supposed to be standard but some tires run wider than others but this estimate should be very close.
2008 IB E92 M3| BBS | KW | Arkym | Platte Forme A.G. | Active Autowerke | K&N | Fabspeed | Dinan | Evolve-R