These wheels are like an anthracite color in the center. The reason I went with these wheels was mostly looks I guess, cause i'll use the stockers for autox and track days.
As todd said, I went with the size tires the dealer recommended due to the traction control. If the size gets too far off balance (IIRC the rears are like 2%-5% bigger than the fronts, height wise) the controller thinks the wheels are spinning.
The tires DO suck. Spun 'em in damp conditions the other day in 3rd gear, but they look kickass. For a car that goes 5k miles a year, i'm ok w/ that.
Wheels are 18"s. I guess it'd be a plus 1 if I had a base model Z, but the touring model comes w/ 18"s anyway. The fronts are 8.5 wide, the rears are 9.5. The lip in the rear is probably about the width of a bill, maybe 2.5". The rear tires are 285s, which yes, it too f*cking big, but I know that, and again i'm okay w/ having a car that looks like it makes 1000 hp.

.....and I plan on high stiction rubber for the stock wheels, which are probably going black, for the sinister badass track look.