Hey bud, nice modeling! I like the concept alot. Just cucrious, could you post some wires of the pole sticking through the car body? Curious to see your solution for the folded metal around the openning. Thanks in advance!
Yes, give more weathering and scratches to the diffuse map.
Also, consider to make the tread top color more dusty and the "base" tire color darker. Look at this IMAGE and see what I mean.
You could work a little more those treads, HERE.