You can get nice results with single stage but a single stage metallic is not going to have the depth a bc/cc job would have. Metallics I usually run bc/cc because with single stage metallics if for some reason you have to do a repair and blend then you end up with a couple panels with clear on them and you can definitely see that. A year later the chance of getting a quart mixed that's 100% dead nuts match to panel paint with is very slim. Color fades a bit or application differences that change the way a color/metallic lays etc.