Nelly's got some crazy rear wavey's in for around £70 or £80 (can't remember) I had one fitted last year and it really works, you do need new brake pads too. You can lock the rear wheel with one of those fitted, it looks cool too
(Then, from experience, you need to fit a corsa rear brake lever and ruin the feel so you keep locking it up and consequently stop using it altogether !)
