cheers for the advice, i have scopes at work but would know what to look for with it

will try that ferrite thing on the radio lead, and running a direct earth. i'm sure its not the radio as the same thing happened on my old pioneer, its defintely the wiring.

switching the HID's on has a significant effect also, nut not sure what i can do about this as i really like having them, and they light the road so much better! maybe i'll try another kit?