Whenever you see a driver following too closely or driving erratically try to get away from them, change lanes, let them pass, whatever. Also try not to drive next to other cars. Stagger positions so if they have to serve into your lane they won’t hit you. Last tip is don’t drive in people’s blind spot when they are in the next lane. Pull ahead of them or let them get in front of you

This Yamaha receiver https://usa.yamaha.com/products/audio_visual/hifi_components/a-s801/features.html#product-tabs

And Ascend Acustics CBM170 https://www.ascendacoustics.com/products/cbm-170se-bookshelf-monitor-single?variant=40047176843318 These are bookshelf speakers but aren’t tiny, sacrifice a couple of inches of space for the better sound. These out perform $1000 speakers.

And a subwoofer, but I can’t make a recommendation

Or if you want best sound for less $ a larger JBL like the boombox or partybox 310