I have a 2010 Chevy HHR LT and I am fixing to take out the stock stereo and replace it with an aftermarket stereo that is a Double Din.
Do I really need to get the “Stereo Interface” (GM3000) like the box that has the new hardware in calls for??

 

If you want to have easy access to switched power, door and turn signal chimes, steering wheel bottons etc, yes.

You might want to check crutchfield,com out for installation help, they have a lot for free.

 

What was your OEM head unit, the Pioneer with amp ?

 

If you get the gm3000 get one that looks like this. The newer thin style without the mounting holes and blue emblem


doesn’t work