Iv'e used some of the cheapo guns over the years (not the HLVP's) and they actually spray pretty good. I know the real body guys would laugh if I showed them some of mine but, I don't spray very much either. For primers I can't see using a $200 to 400 gun.

The real trick is going to be the body work under the paint, the painting conditions and the right solvents as well as the finish work.

I have a nice Binks 69 that I used to paint motorcycles with. It is smaller than a Binks #7, and not a good gun for a car. As far as that goes, many of the cheapo guns (I don't know about the HLVP's) have parts that interchange with the binks #7.