Thanks for the replies.
I also think it would look very nice in all black, but the I would loose the contrast and Ferrari-bricks that makes it look "Ferrari-like". Without the contrast in the engine cover and rear, the whole rear end would simply be too plain which doesn't match with the front - it's already on the edge by having so plain sides between the wheels, but I do like the Ferrari Testarossa-like grills. I'm happy about the comment about the engine. It had to be in this design because I use it to hold the sides, but I guess it's perfect because the Testarossa actually did have a V8 boxer engine!
As said, this car is very experimental. The front lights are not meant to look as if separated from the body, but I'm not sure I have achieved that effect. It's a shame that the hinge control sticks don't come in red and that the Ferrari stickers are of such low quality. For some reason, some stickers just peel off while others hold for a life time.