Hey MrD,
Thanks for the comment on the black wheels. They really do look GREAT on the car, far better than I could have hoped and better than pictures show. Hope you're staying safe while deployed and hope you return soon to a nice, new M3.
Here's some info on the wheels/tires which will hopefully help you. I ordered them from Ben @ Tirerack (highly recommended), w/ the BMW center caps and TPM sensors installed and longer lug nuts and wheels spacers for rears. The tires are Blizzaks LM-60...Front 255/35R-19 and Rear 275/35R-19. They ride really nice. The only concern I have for these wheels (through research on the forums) is these wheels don't have the best track record for durability. These wheels became a big hit with the 1-series crowd and have been known to bend and micro-crack (forgot the real name for this) from normal road use. Something about the size of the wheel combined with the quality of metal, etc. This didn't stop me from buying the wheels since they were the best LOOKING winter wheel/tire combo that Tirerack sold at the time. I suppose time with tell if these wheels standup to the abuse Belgian and Dutch roads can throw at a car
Another option that I would have gone with had I not ordered the Breytons first was Alufelgen wheels. They make a very nice wheels for the M3 (about the same price as the Breyton) called the SF-71, which I believe they also make in black. Here's their email address (sales@alufelgenwheels.com). Just do a search on this forum and you can see pics and reviews of the wheel (all positive), they sort of look like the old CSL wheels.
Ask anything else and I'll do my best to help. Space Grey really is an amazing color. It great at night, in the day, sunlight, clouds...and the black wheels change the look of the car nicely. A friend of mine said it looked like a "stealth fighter" with the grey/black combo.