Head unit install help for 03 ss please
 

I recently purchased a new pioneer single din head unit and am wanting to replace my factory head unit. I have onstar and factory amplifier, I do not care about my onstar working or steering wheel audio controls, only concern is the factory amp still works with new unit. My question is will this adapter work for what I am wanting to achieve Scosche 03+ GM CL2 Interface - Walmart.com ?
I am going to go to walmart today and pick one up if so. Also will I still need to buy a wiring harness or is this all I need to wire up radio? Thanks in advance!

Looks like it will work, but you will need a radio dash adapter for you car as technically your stereo is a dual din and it will give you a space underneath the stereo. I have one in mine and it's nice cause you can store stuff in it, not much but some stuff lol

Yeah it should work and also like ohara said u will also need a dash kit that will fit your car. look online, there will probably be a few different ones to choose from.