yeah but guys i havent changed any of the amp at all. all existing wiring was a-ok on the old headunit. only difference is i have put a new headunit in.
maybe i need filter of somesort?
also not just rpm but a general static noise and terrible humming when the lights are turned on.

so in short no issues... install new head unit ONLY and get issues with interference caused by the amplifier.

did have the headunit earthed in the factory loom like the old headunit, changed this to a body earth and no difference was made.