The best quote is not always the best. Got a full respray done in Moorabin in mid 90's. They were accepted as the best at the time and their quote was 30% over most of the others. A couple of people told me I was stupid paying that much over the norm but after all these years, with occasional polishing, the paint is still almost showroom and the new owner is extremely happy. The people who told me I was stupid have had a couple of repaints over the time, have paid a heap more than I did, and still have ordinary paint. The moral of the story, find the best, don't scimp, don't try to negotiate the price, make sure inside cowls and inspection plates are chromated and don't hang around. Go and do something else and come back when they tell you it is finished.
This advice is worth what you paid for it.