Since now I've ironed out most of my electrical issues, and have recently upgraded my speakers, I'm looking to upgrade my head unit.

If anyone could suggest a few, I'd appreciate it as well as anything that's needed for the swap, wiring harness, etc.

Also, I have plans to put a sub in my trunk, if anyone has installed one, I'm also in search of guidiance/suggestions.

 

Crutchfield, I get my Pioneer equipment and harnesses from them. I just replaced my PITA Clarion this past Spring. Not knowing what factory system you have, here's both schematics.

 

Get one with plenty of ram and highest android version you can or in few years you gonna have to redo the job cause apps you like will end support for your ageing HU
If you have cd changer in the boot use its harness to wire signals back and forward from boot to console all the rest is pretty straightforward job
Replacing the stereo is the most popular topic here (after choosing right code reader), have a look around you will find plenty of info with photos and hints