The way you gave the car a luster really made it look appealing. The clever use of light to give it that warm yet fierce look. The design is very faithful to the real car. Rims look authorative yet something which would be seen on a street racer's car(which is all the better)
Now onto the police stuff about it.
The sirens could use a bit of work, but look impressive nonetheless. The way you managed to give it the cssic police paint job yet keep it sporty with well placed black and white coloration. The detailing is very impressive, with the number of the car placed very well. I like how you put little lights inside the air intakes. You even placed the small yet oh-so-importany side lights ate front and towards the back (correct me if im wrong).
The backrounds are beautiful and well detailed. You even captured the shadow of the car perfectly. Never has a police car been so well done.
The reason I gave origionality a 4 1/2 is let's face it, tuing supercars into cop crusiers isnt exactly new. We've been seeing it since the 80's.
Overall, I give 10 starss due to the well done vehicle, impressive shadows, and amazing detail.