Nice work in progress dude, the BG looks great!
I personally dont like the window tint and the tinting on the headlights. But thats just my taste.
-Remember to fill in the empty space after lowering a car, and make sure the tyres from the new wheel blend in with the old tyres, I usually use a soft eraser on 20-40% and erase back.
-The whole rear wheel can be moved up a tiny bit
- add a bit of blue highlights to the final image so the car and BG blends in a bit better
Good stuff mate, keep going!