audio music / navigation

I've been searching around Crutchfield for a new stereo head unit for my 2012 Regal GS. The Problem is, they don't show any compatible units for the Harmon Kardon Audio system. Has anyone done this before and will anything actually work?

I am installing a subwoofer on my Buick Lacrosse 2007. Where is the rubber gromment that goes through the firewall? Has anyone else installed a subwoofer in there car?

Hi All, I just got an Enclave (I now wonder why I drove foreign cars all these years!) and I use the USB for music. I have several CDs that I ripped and copied to a USB thumb drive. The songs appear in the proper order in the file system on the thumb drive, but when I ask Intellilink to play...

Has anyone done this update via OnStar, and has it improved your bluetooth experience? What changes has it made for you, specifically are you now able to use vehicle audio speakers for navigation and music in addition to phone calls...