It's the angle. the chassis bends outwards here and viewed from slightly above looks bent downwards, where your pic is from straight on.
On a serious note , there is no damage to the chassis where you are looking or bending but i now certain mine is different to Als ?
Thats not a strange request A strange request is asking a guy in the pub bog to take a look at your foreskin
have a look 1/2 way down my resto page 3 http://thelatebay.com/index.php?topic=17161.40 took out the rear wheel arch and some good pics of the chassis -also on page 4 regards marc