Turn off the stereo, hum a tune if ya gotta. Drive as fast as you can to a local bar/pub. Make sure they have live music that night. Grab a seat, enjoy as needed.
I used to spend money on audio equipment in my car. I have never been into the "thump", but 100db of good solid rock was a must for me. After a job that had me driving about 30k miles a year without leaving the relatively small town that I was working in ruined my view of driving as a source of entertainment, I learned to turn off the radio in my car and used the time alone to do just that...be alone. After I started doing that, my propensity to develop road rage disappeared. I wasn't white knuckled by 3 in the afternoon. I was able to perform my duties much more consistently. Most importantly, I was in a better mood when I got home.
Since you're asking for advice, the best I can give is: Stop worrying about the sound system in your car. Invest the money in a home entertainment system if you want to spend money on that luxury. Any money that you put into a car will be lost. Absolutely, emphatically, and without a doubt.
OK, lecture mode is off.
Crank it up!!