just say you saw them egging your car and they got away before you could do anything about it. You and your friends are the eye witnesses, along with the shop clerk's testimony, you're set. Present this info to the parents, with the video of the egg purchase, and say you don't want to resort to legal action. Get a quote for them for your repairs and show them. Then you're set!

Most parents would definitely bail their kids out of legal trouble. Kinda feel bad for the parents though...UNLESS THEIR RICH!