I've been out mobile audio for too long. When I was heavy into it, I ran a Clarion Audia cassette head unit with DBX noise reduction feeding Carver mobile mag amps to power JBL 3-way 6x9 speakers with titanium tweeters.
I was more a rocker and preferred the base of the JBL products over the softer Polk. I still have JBL towers, studios and sub for my surround system amplified through Pioneer Elite integrated amplifiers. My oldest system has a Technics turntable with Grado cartridge powered by a Harmon Kardon integrated amplifier running Advent bookshelf speakers and a dual driver sub woofer.