Can I also add to that that you should be able to paint the interior, stripes/two tone (where applicable) and each individual colour of a race cars livery (for fantasy liveries like fgt and lm race cars of course, not real race liveries).
This is a great idea and is the next logical step for GT customisation. I reckon it would have to wait until GT7 as it would take up additional memory. It is probably not much but GT6 is stretching the PS3 as it is.
It would be nice to paint the roof in a carbon fibre or aluminium effect.
And it's sad that it is so easy to do in Forza Motorsport and Polyphony doesn't move a finger to compete with Turn 10 (even the paint job being awful to me haha)