To me this doesn't feel much like a time attack car - it seems a little too well built
I think the problem is the heavy use of a single donor - the old bmw GT2 car.
You've had a good try at fitting all the parts, but you've lost a lot of the new shapes of the F82 M3.
Using a studio car for a donor also means you've lost any reflections, so it looks a little bit fake
Keep practicing, and I wish you luck for the competition