Spraying automobiles takes a big compressor or a lot of patience and elbow grease. 60 gal, 220v, and about 14 cfm at a bare minimum for most entry level hvlp guns. Of course you could use a much smaller compressor (a lot of people do). It will require lots of down time waiting for the compressor to catch up while you are spraying and there will be more surface defects to color sand.
I use a "hobbyist" setup and end up with marginal to decent results - harbor freight compressor ($380) that meets the above minimum criteria, 35' of steel plumbing ($80), a devilbiss finishline3 gun ($130), and devilbiss finishline watertrap/filter ($120). My paint jobs always require extensive color sanding.
