That's why I was looking for one with an SD card NAV. Easier to upgrade. I bought the Soundstream used for my Frontier but traded it in for the Liberty so threw it in there. I like it. It is very straight forward and easy to use. Mine is a few years old so I don't think it has Sirius built in but when I had mine installed I had them hook up my portable sirius player to an auxillary port so it works great. (I have always had a portable sirius because I use it in multiple vehicles and as an mp3 player). It has multiple Aux ports, an SD slot for music/movies, an ipod hook-up, USB port, and plays DVD's, CD's etc.
The thing I don't like is that the brand is kindof obscure (at least on the east coast). Since I bought mine used it didn't have a NAV antenna and apparently they refuse to sell one separately (I fhad to find one on ebay). Also I believe that a lot of them now have an SD card Nav slot built in to the radio instead of a seprarte modul (which costs more). But, I can actually buy another separate module and get satellite TV for it as well if I want

(not sure if you can do that with some other brands).
I looked at some new ones at Bestbuy, etc., and it seems that you can get a new Kenwood, JVC, etc., for around $600-$700 which I'm sure is much cheaper than a factory stereo, especially a 2011 factory stereo.