Hmm . . let me think back to my old mischievous days . . looks like it's time to have fun with shit.
-get a turkey baster and pump shit into his exhaust.
-rig one of his outdoor lights with a bag of shit and an M80 (break the bulb and put the fuse by the filament)
-if he has a roadside mailbox, spring load a container of shit so it pops out when he opens the door.
Of course you can't do any of this now, since the cops will have probable cause on you & your friend. Just make his ass pay for the damages to your car. You have witnesses, so you're good to go on that.