chevy cobalt 2007, what do I need to change the stereo?

[thechriscloud]

I have a chevy cobalt 2007. I know I need a mounting thing but I heard that I need something to keep my electronics working right. what is it? Dont tell me that I need one, but what is it called or the item number or something....THANKS!!
I have a chevy cobalt 2007. I know I need a mounting thing but I heard that I need something to keep my electronics working right. what is it? Dont tell me that I need one, but what is it called or the item number or something....THANKS!!
ok oops above....

I have new speakers, a sub and amp and a head unit. I know how to hook all that up and what I need, but what I dont know still is this mystery thing, possibly a harness, that cobalts need for the electronics to work. what is it called?

 

[mcperson2k]

Head unit, and a conversion kit for that specific car. If your getting new speakers and a sub, than your going to need an amp.