What series is your Beemer?
You could probably paint a 3 series convertable (jambs and all) with 2 quarts of Concept, and have paint left over. A coupe would take another pint. I would not do a base clear on a solid color (non-metalic/pearl), it's just more opportunity to get it full of garbage, and uses more material ($$$$).
As has been mentioned above, get the right color mixed according to the color code, and check any variants, pick the closest one, you'll do well.