I have to reinforce what Overseer says, preparation is everything here, it really is. The paint and lacquer finishes are 100% dependant on the work that sits below it.
The problems don't stop there though! - Not only should your car be perfectly prepared, but the area in which it is sprayed/prepped will have a major effect on the outcome. If you just stick it in a garage or a barn to spray it, you have to think of all the airborne crap that will attach itself to your freshly painted baby, which will ruin any prep you've done on the vehicle itself. You ideally need a very well ventilated sterile environment in which to spray a car.
There is also a science behind the actually paint mixing - Paint, thinners, hardeners, lacquers, its a pretty complex set up.
I have no doubt that you can become proficient with a spray gun Vix, as its definitely one of those skills that can be learnt, so practising on panels from a scrapper will improve your finish, but all the other aspects make spraying one of the hardest jobs for the modifier to do themselves.
Sorry to be the depressing one saying "Don't do it!" but I can't imagine how upset you'd be spending a couple of weeks sanding, filling, degreasing, primering, spraying, lacquering, cutting and polishing to end up with a finish that you aren't 100% happy with.
I have a friend that is a bodywork/spray job guy for a living, and has his own unit for private work, with the previously described spray booth (ventilated sterile environment). If you can bring your baby up to my part of the world, he'll give you a good quote, and the results will be superb, trust me.
As a fellow golf owner (he has an immac Oak green Big bumper Valver) you should be able to tap him up for a 'Fellow GTi driver' discount!