I can see where you are going with this. If you search for images of the Bugatti Veyron (slobber!) there are loads shown with a black bonnet/roof over a blue body. However, the very defined bonnet on the Veyron gives a clear boundary where logic dictates the black paint should stop. The Crossfire is a very different animal. I personally like two tone jobs, but I think your proposal lacks subtlety, and the transition point between the two colours doesn't work (to my eyes, at least!). However, it's your car, and it is not for me to stop you if the design works for you.

Whatever you decide to do, have fun!