Feedback form speaker

Hey finished installing my RNS-E into my B5 S4 and everything works great, was just plug and play basically. The two problems I am having is that one I am getting feedback from the speakers and two the unit after a CD is loaded from the changer, it loses power but not completely. The screen fakes like it turns off and the speaker fade then come back to full strength. About the feedback, it basically mimics my turbos. It sounds like a dentist drill and goes along with the turbos or revs. I know it is feedback cause when I turn the unit off it doesn’t happen. Any help of info on the two problems I am having would be lovely and so far I am having a blast with the RNS-E. About to be brave and start cutting it up to fit better. Thanks very much.