You'll have the Lux amp. I just did this on my Denali which also has Bose.
I bought a Pioneer NEX-5000, factory refurb, from Sonic Electronix. Absolutely love it so far. They threw in a Scoshe dash kit for $Free.
My Denali has rear-seat entertainment, which I wanted to keep if possible, as the Pioneer head unit supports it. I found the right adapter and the entire install was truly plug and play. I got the PAC RP5-GM11 from Amazon for about $100. It was the
only adapter I needed, and ties in to both the audio wiring and the body wiring. That means if your new H/U supports a backup camera, the PAC box will send the right signal when you put the truck in reverse, and the H/U will go to the right input. It will send the speed signal for navigation. Things like that.
The PAC box supports steering wheel controls, RSE, OnStar, backup cameras, and includes a "chime module" that you may or may not need. My truck would chime with no radio installed so I didn't need to install the separate module. I had Bose audio and the TNR touchscreen nav. PAC says to turn the key to "run" with the radio pulled, and see if the truck chimes. If it does, don't install the module.
They make it very easy to install, all I had to solder was the 12ish wires from the Pioneer harness to the one PAC harness. Then, I just plugged things in where the PAC box was labeled (the box supports "Amplified" - aka Bose - and "Non Amplified" systems alike).
Pix of the new H/U - love it so far. Was $499 from Sonic.