So I have a 2013 402A Sony Package. Stereo is good for my needs, but sometimes I miss a quality system. Problem is its been 15 years since I last touched a stereo minus my Sync 3 upgrade, and most brands I knew back then are either junk now if even still in operation. So what have you done for upgrades TO THE SONY SYSTEM. These are a few things I've looked at based on Google and recommendations, but is this overkill? Figure this would help fine tune the existing system and also give an option to add a sub later if desired.