I have a 2011 Highlander. Base model. No sat tuner. I have both the antenna mast (front passenger side) and the black puck XM antenna (rear center). I went to my local Toyota dealership today and the parts dept told me that Toyota factory always installs the sat antenna (black puck) even if a tuner isn't purchased/installed. I'm not sure what model year car you have, but I would think if you have the black puck, you already have the XM antenna. I also don't know if they can be color coordinated with your vehicle paint job. Our car color is "green money" but the puck is still black. The antenna cable should terminate under the driver's seat.
Even though the antenna is for XM radio, I decided to install a Sirius tuner. I'm going with the ISTY11 ($113), SCC1 tuner ($48 - $30 rebate = $18). This configuration should work with the radio head and steering wheel controls, so I'm very happy about that. I didn't go with the Toyota XM Tuner (~$229) because, for whatever reason, a Sirius subscription costs less than XM - and I prefer Sirius over XM anyway. I don't know why. They are the same company. But, it is what it is. I've had both Sirius and XM in other vehicles/boom boxes for several years. Can't beat satellite radio.
I will install the sirius antenna that comes with the SCC1 until I can find a low price xm-sirius antenna adapter.
Good luck.
Links to the products I talked about
:
http://www.buy.com/prod/siriusconnec...204832843.html
http://www.siriusxmrebates.com/stati...06_English.pdf