Hey Sean,
Let's chat. I have a lot of experience having airplanes painted, in the Texas area. In some ways these paint shops are similar because they are familiar with fiberglass. In others, they are different because it is not always a state of the art $million paint booth.
I would stay away from water based urethane's, as I've had terrible experiences with durability and adhesion. I had a motorcycle tank painted 4 times with water based urethane, and it pealed off like masking tape. These paints were forced on some shops by the EPA. I finally went back to the solvent based paint, and it sticks like............paint.
The next question is whether you want a single-stage, or two- stage paint. Single is just color, and two-stage is the color base covered in clear. The two-stage will hide some of the imperfections in the fiberglass as you can build up the clear and buff it out. Single is cheaper, and can also buffed.
The biggest expense will be the labor involved in prepping the fiberglass. It's terrible work, but if you do it yourself you will save a lot of $$$. As previously stated, you will never get it perfect. You can always fill and sand it one more time. A local shop should be able to do a good, single color paint job for a reasonable price if you walk in with the body ready for primer and paint.
If you want to detail you car in race livery you will have to decide if the numbers and stripes will by vinyl or paint. Vinyl is cheap and easy, but if you don't replace it every 5 years or so, it will begin to crack and is a pain to remove. Painted stripes and numbers can be incorporated into the base coat and then it all can be sanded and cleared to give you a smooth, deep look. However, it will be the most expensive.
A local shop stripped and painted this airplane for less than $15K. Four color metallic, complex job with overall clear.
Your car will have much less surface area and I'm guessing it would cost half the price?
Give me a call or text and let's get together one day soon. I want to pick your brain about the RCR and see your project.
Jimmy Cash