I had real issue with the Harmon Kardon system when I first bought my 19’ Limited. I would complain about it all the time when in for service. Dealer always said nothing abnormal. Finally one day, I came across a TSB on it. (might even have been on here) I showed the dealer service dept. They had never heard of it so they ran the fix.
Man…what a difference! Brightened everything up and increased the base and volume.
For me, now, it’s not worth the effort and cost of swapping out speakers, subs or amps. It has plenty of oomph enough to rattle the change in my consul.
I’m alright with the cars 3 rows over not listening and singing along LOL