I did this swap a few months ago. My LTZ originally had the regular/no-frills radio with XM. I scored a Nav unit off Craigslist for $150 and sent it to Greg at CPS A/V in California to be programmed to my VIN. He traded me for a non-DVD Nav unit since I don't have the rear DVD overhead console. A DVD unit would work, but could have processor and overheating issues because it's always trying to find that missing module. If your current radio has XM, then that will work with the new head unit. The Bluetooth stuff requires a separate OEM module that is so equipped, but it still only works for phone calls. The non-DVD Nav unit I have has a USB input, so I use that for streaming music from Pandora on my phone. It can control an iPod or music on a USB thumb drive.
I did the swap mainly to have the USB input, touchscreen and reverse camera functions. The OEM navigation does suck, but that wasn't enough to make me spend $700+ on an aftermarket unit and I have plenty of Garmins floating around if I ever need sat nav. I'd like Bluetooth music streaming, but that's not a deal-breaker. I plan to relocate the USB input from the dash to inside the center console so I can leave my iPod or phone plugged in there and not have the wires all over the console. I guess I could get a USB Bluetooth receiver and stream music wirelessly. Maybe I'll look into that one day. It cost me $100+ shipping to Greg to have mine programmed. Some dealerships are capable of doing this and possibly for less. But, I read of too many horror stories of people having their radios bricked because of dealership error. I felt that having Greg do it was the safest route. So, factor in $100+ into your radio budget. All in all, I have about $300 invested in mine, including the stupid expensive OEM USB dash cable and OEM USB dash port. I would've spent $300 just in the adapter/interface modules had I went with an aftermarket head unit.
So, you can get what you want. You just have to know all the details going in.