Dear Friends,
I would like to add a little clarification here. Paint booth is to control dust, humidity, temprature etc...but it does not automatically mean that a car painted within a booth will be great. what you need is a special TYPE of paint known as 2K. ICI, Silken, and Standox all offer 2k paint. As rightly pointed out by someone this type of paint also requires special hardner and thinner. This type of paint (2k) will NOT fade or yellow easily but is more expensive than regular paint.
My advice is that if you love your machine/wheels than at least go for 2k paint...it can be the cheapest one...and it can be painted outside the booth if proper care is taken to avoid dust. Direct sun light in the summer is also great in baking it to a hard gloss in just a day.
I normally sand my 2k paints after the 2nd day. one night in the booth followed by parking the car in sun light in the 2nd day..and then sanding and compounding in the evening of the 2nd day.