Nice job. As mentioned not that much done, but what has been done looks nice. Both from a design point of view as well as quality. The venturi in the back does look a bit blurred over the patch you have added there where the numberplate used to be. Could probably be fixed with the use of some smart selections using pen-tool followed by some normal brushing.
I like the choice of rims, really make the car more aggressive, but they stick out a bit much. Can't put my finger on why, but I am guessing it's lighting related. Maybe if they were dulled a bit and put back on the original tyres they would look better.

Maybe?
The bg change is really nice! Car sits perfectly in it, and it's a cool background. Only question I have is if it should be blended a bit more, as in the colors changed a bit more. But it's so little that I don't know how. Hehe. But the car sticks out a little, so a little more had been nice, but it's marginal.
Overall a really nice chop!

Keep it up, but maybe try to do a bit more mods next time, I think this chop shows that you can, and deliver with quality.
Cheers!