I really wouldn't wax it before the paint has had time to cure. I think you would be sorry in the long run. If you spend the money for a repaint, it would be a shame for the paint not to turn out as good as it should. If I were you, I wouldn't go to the show. I'm not sure about the shows where you live, but most of the shows I've been to, the stupid kids get all close to your car and rub up against it. This is no good if you don't have anything to protect your new paint. However, if you have something to put around the car so people can't get close to it or if people there don't touch the cars then you should be fine with no wax. You would probably be pretty safe using quick detailer to give it a nice shine at the show.