I had an Audiovox PNP3 installed in the center glove box underneath the
radio of my '05 Accord EX.  It's basically the same unit as the Sirius
Sportster.  The installers (Tweeter) installed the antenna on the trunk
(magnetic) running it two inches away from the rear windshield.  I purchased
a Soundgate SNHOND3 Aux interface that replaces the XM input on my radio
(don't care for XM!).  It acts as a CD Changer input (works with some Sony
CD-Changers as well).  With it, we ran an RCA cable from the Sirius receiver
to the Aux interface for direct sound without the FM transmitter degradation
in sound.

Isidoro Pulido