Really considering upgrading the Lexus stock audio on my 2013 GS450h and was wondering if you guys have any suggestions on where to begin?

 

What was the follow up on this?

 

I got a few answers. One person suggested that I redo the whole thing. Like get a sound processor, 5 channel amp, 4 speakers and a sub in the back, but then I also got more than one response saying that the audio quality really isn't that bad and that the one thing that would make the biggest difference would be to get a decent sub in the back to play the lows and have the speakers play the mids and highs,

So like a 12 inch Alpine type-s or type-R sub with a mono amp and controller.