Lovely motor!
Regarding the 400D - when photographing a white object it's always worth taking a custom white balance reading and using that to get a photo with 'true' white as opposed to an off-white that you often get with default camera settings that are designed to suit all light conditions.
It's easy enough to acheive: just hold a white piece of paper in front of the camera, photograph it, choose the custom white balance setting from the camera menu and select your shot of the paper when prompted. This will then give you a true white.
Loving the car park shot btw.