Some cool ideas here dude, I really like the track style to the car, from the widened rear arch and missing bumper, to the new rim colour - it works really well.
You've had a good attempt at the new window reflections too, but I feel they need to be brighter

The brushing is coming along nicely too, it just needs more contrast -> look at the base for reference, you'll see that most of the front bumper is much darker than yours - you should use this as a guide.
I think the main problem is the background though - it's not at the right angle. I think the car is a bit too small, and the track that it's on slopes down too much, so it doesn't really fit
Good try though and some cool ideas

Keep it up