For small jobs like a receiver I personally think the airbrush is better.
The HPVL is for larger jobs or "mass production".
HPVL will do a nice job, but you can do a perfect job with a high volume airbrush and a good air supply.
Trying to do it with hobby type canned air is tough out of any system.
A lot of hobby shops and art supply stores sell airbrushes and offer a lot of good advice.
I'd talk to them, then quietly go off and buy the airbrush online where the prices are best.
Again, the simple single action cone-feed airbrushes will do a great job of spraying the heavier gun type coatings if you do your job right.
Practice with cheap paint on scrap is a great way to learn airbrush control.