Not bad mate,but with some more time spent you could have had it much better.
Overbrush of the body and side looks good, but you should have changed the ways of the refs on the side panels as it's still reflecting trees from the previous background. The mesh on the grille at the front has far too much shadow, and also would be nice to see th emesh on the bonnet vents. Front bumper like mentioned, the vents are poorly cut and dont have enough highlights around the outside to show the depth that they belong there. The IC Pipes look like their floating too. Rims are nice, but rear needs to be wider.
Another few silly mistakes is that you have a right bucket seat in the interior, but no left bucket seat. The new background hasn't been blended through the windows properly. Your right front window is showing light grey/blue, it technically should be darker and matching the details on the wall beside the car. The over-brushed reflection on the mirror is also wrong (just like the side like already mentioned).
Other than that it's good, just look out for silly mistakes.
