earl, maaco, do it yourself auto paint, or both?

I have a  93 Dodge Spirit with170,000 that still runs well. The paint has
had a history of peeling off to the primer, since i bought it in 95.  The
dealer made good on repainting the hood back then, but since then, i've had
to spot it with touchup paint and the like.  Now i have a big area that's
peeled to the grey primer on the roof. Obviously I don't want to sink a lot
of money into a paintjob on a car that will only be used for another year or
two.  My choice is to bring it to earl, maaco , do it myself somehow cheaply
(if possible with a top of the line Wagner powerpainter), or do a
combination of sanding myself (as some suggest) and taking it to Earl or
Maaco.  Is it possible to shoot any type of auto enamel with a top of the
line electric sprayer. (It sprays thick paint like latex with no problem, as
I've painted garage doors with it.) Email replies to [EMAIL PROTECTED]
and thanks.