Help me choose a spray gun for auto surface refinish?

I want to buy Rongpeng Brand Spray Gun to for our workshop, there three type for choose, but I don’t know which model to choose？

Rongpeng Brand Hvlp Spray Gun A604 with 1.4 or 1.3mm nozzle •Forged gun body, no air hole in the gun body.

Rongpeng Lvlp Spray gun R500 with 1.3-2.0mm painting nozzle: Much cheaper than A604 & A605, but is very Cost-effective.

Rongpeng Hvlp Air Spray Gun A605 with 1.3mm nozzle: Top grade Hvlp spray gun for all kinds of surface and professional using,especially for automobile finish painting.

three of them all very interesting, give me your idea.