Well after finding that there was a slight humming noise coming from my speakers when the lights were on and the pitch of the sound varys when you use the dimmer dial to adjust the brightness of the interior lights. I decided to go to my location Mitsubishi dealer, actually where I bought my car, and confront them with this problem. They said " yes we know about this problem and a lot of people have been having the same problem and they offered to fix the problem for free as it might be a factory fault or something like that. Anyway I said don't worry about it for now as I have just bought a new head unit and if I have the same problem after it has been installed I will come to have the problem fixed. No worries thay said. I had the head unit installed and the problem of the humming noise was fixed no noise at all crystal clear. The next problem was when I listened to CDs on the new head unit the aerial would stay up. As it would retract with my mitsubishi stock unit. Apparently some head units leave the aerial up constantly when the unit is switched on which I didn't like because it looked like crap! So went into the boot and disconnected the power to the motor of my electric aerial. It doesn't come up anymore and it looks much better when driving around town with the aerial down instead of sticking out of the back. Still pick up a good radio reception with it down.