I had a Porsche dealer install the SiriusXM unit from a Cayenne in my 2007 CS4. It seems that any time I drive past large trees or electricity poles with transformers on them, I lose my signal. The system doesn't have one of those "shark fin" antenaes so I wonder if that's why I get such intermitent reception. Anybody else experiencing the same issue? Is there any solution? My wife's X3 has a shark fin and she doesn't have the same reception issues.