Not sure if anyone has noticed/posted but I found out that you can rewind, pause and FF Sirius sat radio. When under the entertainment tab click "Replay" at the top right of the screen.
I used this all the time. I'm an old fogey (43 yo) who listens to a lot of talk radio (at least it's sports!).
I'll have Sirius 91 (College Sports) paused and filling up the digital recorder while listening to live terrestrial radio. When the live radio hits a commercial, I switch to sirius and listen to what has been said.
Also, FYI, you can skip through individual songs and commercials with a tap of the forward button on the steering wheel. It will go to the next break or song on sirius radio.