I know a local lad whos selling one for £100, but as El has said not really worth the hassle as everyone seems to sell them on after short periods of time due to getting into trouble or the noise doing there head in.
i had one on my pulsar and mate the thing only lasted one week !! so nosiy and in the end didnt sound all that if im honest so put it back to standard and it was music to my ears !!!!! but up tp you pal .