The 12 will be a tight fit, but with the perfect offset and 315s, it should do okay. I may need to take the dust shields off the shocks and get relocated bump stops, but it's definitely been done. Some super snake owners widen their Alcoa wheels to 11.5, 11.75, or 12 inches and are using that to fit a Michelin or Pirelli 335/30/20. That's a monster of a tire, but guys get it to fit with a watts link. Pan hard bar allows for too much lateral movement at that point. I'll be a comfortable ~20mm narrower than that setup (with the option to put 335s on when/if a watts link gets installed)
Color? I was between a matte titanium grey finish, or some sort of matte bronze. I refuse to do flat black. It looks good, but it's too common.