Dozzer,

Check the old paint for cracking or peeling. If you can see cracks, you can't paint over them! The new paint will eventually crack in the same place.

The cheaper paints don't hold their color, or gloss as long, so use a light color, or she may have you repainting in 5-10 years.

Check this site for old paint threads. They will give you the benefit of many people's experience.

Ask a local body shop if the spray gun you have is a good brand. IF it is, you might be able to have a nice gun for the cost of a gallon of "gun cleaner".