I have two Devilbiss HVLP guns, one of them smaller than the other. It seems like it might be more of a hassle to break out the gun, load it up, and clean it out for each use when a spray bottle is always right there. I'd also be worried about having an entirely metal HVLP gun accidentally scratching the paint. Then you run into needing a foam applicator if you decide to use a gel on the tires.
Mark