You really want to keep you info on a vehicle sign simple and to the point. People usually only have a few seconds to read the info on your sign. Name and contact info is all you really need. the more info on the sign, the better chance you have of them not getting to the important part like your phone number. Also, keep the font basic, something that is easy to read from a distance. you also might want to shop around the sign shops in town, their prices could vary quite a bit.