Why don't you just plug your receiver directly into the Aux jack? That's what I did - bypassing the FM issues. I'm loving it!

"I will warn you the reason I say this is the 'best sound' is there is a grounding issue so I get a slight buzz sound when I have my Starmate plugged into the power outlet." I'm not noticing any buzzes, and I'm using the Starmate, too. Hmmmmm. Maybe it's the adaptor you're using. We're using one made for the Starmate.