Black is best overall colour for the following reasons:
1. Functional. Shows off the wheels, but not the plastic trim.
2. Iconic. It's a classic GTi colour-can you think of any other car that looks really good in black. (There aren't that many, Maybe 911's look good?)
3. Co-ordinated. It fits in with everything eg the black headlining, the overall sporty image.
Against blue:
1. Considerate. Looks best on 5 dr versions-more family orientated.(Mother-in-law-may approve)
2. Soft. Image-possibly at odds with basic "drive-me-fast" concept, it's not mean't to be a "nice" car.
3. Some shades, not necesarily this one, can 'date' quite badly in a a short space of time.
I have always had a black car by the way!
