hi mate, I don't know if you know, but I do a bit of car photography and use the Sony A200. ( www.facebook.com/sdukphotography
I LOVE the A200! I have the utility lens that you have, also use a 50mm fixed lens and have a 75-300 lens for motorsport shots.
Are you shooting in RAW? This is by far the best way to make sure you get "the" shot and allows for much better editing back home.
What mode are you shooting in?
Do you have any of the RAW files for the above photos? I'd gladly have an edit of them for you to see if I can change your mind on the camera