Damn, that's really rough. It won't make you feel any better, but I was staying at my friends house the other day and we caught kids egging the house and their cars (also very nice cars... SL63AMG, Z06, 7-series, customized Jeep wrangler, Mercury truck.) I was thrilled that I finally got to deliver a beat-down. My cars get vandalized sometimes, too, and nothing boils the blood like that. I hope you figure out who did it. I figured out who broke my dad's windshield on the '72 Impala and took out my anger on their cars. Childish, maybe, but I'm a child.
Good luck getting it fixed, and just remember that God (or whatever you believe in... Karma of some sort) can get these kids back better than you ever can.