My husband and I are debating on getting SiriusXM. He has a 2007 Monte Carlo that's already had it installed (his dad had the car before him & had the satellite radio), and I have a 2004 G35x.

Since I'd be using my iPhone for the Internet radio, my thought is that I'd only need a phone mount. I do have a satellite button, but have no idea if that means the car had satellite radio before I purchased it or not (the SiriusXM rep I chatted with online wasn't able to tell given my VIN).

I guess my question is: Does anyone else just use a phone mount for SiriusXM radio via their iPhone with a mount, or do I really need to see if the car itself is equipped? (I hope I made sense here!)

Unless you see a satellite antenna "puck" on the rear of the car, and the radio goes to the sirius help channel when you push the SAT button, you are only wired for satellite.

If you want to add satellite radio, I'd recommend going aftermarket with the headunit, since that will give you much better iPhone connectivity options in addition to allowing a satellite radio adapter to be added. With an aftermarket radio, the iPhone will be controlled (Pandora and other streaming internet radio) via the headunit, so you won't have to ugly up the interior with a mount, and just keep it in the glovebox or center cubby.

Okay, so then I'm definitely only wired for satellite. Forgive my asking, but what do you mean by headunit? There's an accessory for XM that allows you to plug in to the car lighter and stream via an iPhone, which is what I was thinking of getting. However, I'm trying to learn all of the options before moving forward.

Headunit is the main radio.

Why buy an adapter when the Sirius app is free?

From what I can tell, even though the app is free, you still have to get either their in-vehicle or Internet subscription. And since I would be using my iPhone, I'd let my husband have the in-vehicle subscription and just add on Internet for $3.50 more a month.