Did this radio improve sound quality with the existing speakers?

 

The sound quality is pretty decent. I haven't really had a chance to do much testing yet. I do have some high-line speakers (Harman-Kardon) from my parts truck installed in place of the original ones. It should be possible to install a different amp instead of the OEM one under the passenger seat, since the Metra harness allows you to connect to the factory wiring that would give you most of the inputs and outputs you need down in that location.
I just wired together the Metra RCA harness and the harness for the new headunit. The AMP-CONT wire does seem to work to initiate the OEM amp; I may not have held the connection long enough when I was testing things before.

The headunit as delivered has a reasonable audio player app, but it's pretty straightforward to install something better like Pi Music Player from the Google Play Store. CoPilot will install nicely as a replacement for the onboard GPS. I'm currently working on installing Headunit Releaded, which works as a substitute for the full Android Auto suite.

 

I didn't use this head unit but a Kenwood single din and yes the audio quality did improve greatly with the stock speakers and amp under front seat still in the signal path. So the problem with stock sound is not the speakers.

 

Thanks was hoping to hear that. The stock radio seems to only put out mid-range