LVLP Spray gun

The cheap harbor freight gun works great for primer.
I've painted both my cars and many others when I was a bodyman . I bought a kit like this. I used one gun for paint color only and the other for clear only. Then had one more for primer only. The metal cups are better for clean up after. The key is what size nozzle tips you use
https://www.amazon.com/dp/B001N1E9Y8/?tag=fabo03-20
Eastwood Guide to Paint Spray Tip Sizes for HVLP Guns | Eastwood Blog