I actually swapped out my HU with a friends of mine HU, and lo and behold...no noise! e-mailed Rio on the issue and was told to send my HU in for servicing, all expenses paid by them, as to them it sounded like an output problem within the unit itslf. Hopefully they will be able to find something and I will be much happier!!!

Will keep u posted on the outcome
_________________________
...One man gathers what another man spills