The gun you're looking for will be a HVLP top feed gun, the one that has the cup above the gun. The bottom feed ones work well enough, just is you won't be able to get all the paint out of the bottom so the top feeds are prefered. Get a good brand, spend a bill or two on the gun. Don't get the $20 cambell hausfield special at the local hardware stove. I've got a Binks I picked up used, it's a bottom feed gun but honestly it's a fairly nice end piece and for $30 I wasn't gonna gripe. The cheaper guns probably won't atomize nearly as well, and your paint job probably won't come out as nice. A seperate regulator and a de-oiler/line drier are a good thought, any lines you run past the de-oiler/line drier MUST be clean. Also, be *very* meticulious on your prep, if your prep is ****ty you won't like the paint job. I don't do cars for a living, but I do paint for a living and I know bad prep when I see it!