I tried playing around with shadows/highlights today and I'm really not sure if I like the results. Examples: (note: the differences are really subtle. You might want to save them and just click back and forth)
^ Just some imageshack servers being slow and fail
So which is edited and which isn't? I can only see one version of the second picture (because of imageshack serverside fail), in any case the second one of the first picture is better.
I don't like the first of the first because the shadows have no detail, the wheels are just dark abysses from which no light can escape. The second of the second just looks underexposed.