How do I upload pics?

Red is the hardest color to spray on a car... Because the pigment is so thin, you can get a lot of read through.

Going from red to black will not be an issue. You'll be fine there, just make sure your painter hits all of the crevices.
 
Any good paint job should cost you at least 2-4K dollars depending on what is done. I've seen a few cars painted for more, but well, those cars were flawless when they came out of the shop.

Good luck with the new project.