The Coupe's factory sirius is located behind the passenger seat underneath the plastic bulkhead cover. It is a very small box, maybe 4 inches square.
I was able to get the RB1, Factory Sirius, iPod and UConnect to work, including the artist/song info for both Sirius and iPod. The information is posted in the "Illustrated Upgrades" section of the forum. It is post number.
I took pictures, but will not be able to post them for a little while. The real trick was NOT using the Artist cable, and using the cable PN 5066203AA instead.
PM me if you have questions.
Good luck!