I agree with Mark, put it back to standard and get it put through the insurance - I've seen cars written off for less!
How's you boot floor? Does your tailgate open and close funny, if at all?
He's hit that hard! Gutted for you mate!
Feck that, start the insurance claim, and contact the police.
This kind of thing really does me off, the person i rear ended, she was fine when i spoke to her, next thing i know shes claiming for *ucking whiplash. People are too eager nowadays to jump straight on the whiplash claim bandwagon.