Car photography is still tricky to me. It is difficult to take pictures with people walking about at a car show. Then on top of that the sky was overcast and colors were flat and contrast low. So what do you do?
Well, shoot with exposure bracketing, and hope you can save some pics in post processing. Pop over to a good HDR group such as http://www.flickr.com/groups/hdr_photos and you will see how effective a little HDR can be on man made objects such as cars. So, below my try at saving what is otherwise a pretty plain photo.
Canon 600D, Tamron 18-270mm f3.5-6.3 Di II VC PZD. Focal length 39mm, Exposure 1/640sec at f8 +2/3EV, ISO 400, Focus auto, VC on, Flash none, Filter none.