Awhile back I bought a ca. 2008 Pioneer AVIC-F700BT ("Flash Memory Multimedia AV Navigation Receiver" it says on the box) that was pulled working from a GM vehicle (presumably the owner sold the car and hoped to reuse it or sell separately) and everything's there, clean and neatly packaged, including the interface to keep the chimes/turn signals (and Onstar which the car doesn't have anyway), so I'm optimistic, that it would work without buying much else, other than a subwoofer to go in the unused spot in back.

Thinking about putting it in my 2008 LS and wondering what issues I might not foresee.

Update - wow, thanks for the tips! Gaining confidence, figure if all else fails I can put the stock unit back in. :)

 

You will want to pick up a dash kit for your HHR and ensure you have the correct wiring harness. Since it's an avic model deck you should be able to get away just grounding the parking break wire (the newer units require a pulse ground switch to work).
As long as you have the dash kit and appropriate wires, it should be a simple radio swap.
I don't check here often, but please send me a private message and I'll get you my cell phone number if you run into any issues.

Have an awesome day!

 

You'll also need the GPS antenna.

 

I just did a avic5000 in my car with a factory sub box, aftermarket Pioneer sub & amp. The whole thing is pretty straight forward but every time I thought I was FINALLY done there would be an incorrect adapter or bad GPS antenna or some other issue, The putsy stuff never seemed to end. Keep a 7mm nutdriver handy for a while.

My car was a crashed unit and it literally took me longer to sort out the radio crap than to complete the rest of the car.

All of that said I am super happy with the end result.

 

You may want to look at the website AVIC411.com as I used them over the years with both my Pioneer head unit installs. Very handy info and the cover how to handle most any issue that can come up. As noted make sure you have the correct adapters for the HHR LAN bus, steering wheel controls and On Star if you use it. There is also a special antenna adapter since the car and head unit use different size plugs. Make sure to get copies of the Pioneer install manual and user manual so you can see what wires go where. On mine, the car's wires had to be cut from the factory plugs and the adapter wires were the same colors so I had to solder them and cover with heat shrink tube to insulate them. There are different GPS antenna wires depending on the Pioneer model as my X850 and X950 had different ones so you'll need to get the right one for your model.

Hopefully there is a good and trustworthy stereo shop where you can hang out and see what you'll need close by? One nice thing is there is no programming required with a Pioneer unit if you get the correct adapters!!!