[masraum]

For the first photo, I actually like the composition except for the pole and the sign. With the motion blur and the space in front of the car, it looks like the car is getting ready to streak out of the frame.
The first photo could use some color adjustment, maybe just saturation or possibly a little white balance to bring out the green and yellow.

I've read several times that the best lighting for photographing cars is actually a bright overcast day. So you don't have the sharp point source of light from the sun. Granted, that's not always something that you can arrange when the cars are around.