Spotted two in one day; Rare because I never seem to run across any others.
Sunday morning, Mineral/Dry Creek heading east near University I saw my twin. Juarez Black sedan... I was driving my 300zxTT at the time for a mile or so.
Sunday afternoon, on Arapahoe near University headed west was a space grey sedan. I was in my M3 at the time pulling out of the Southglen complex and he turned toward the ice arena. Waved and gave an engine rev.