Anyone have any experience in car audio?

I Put way too much money in mine (Focal utopia components and 11" utopia subs run in stereo with a Esoteric Audio E7402 and Zapco Competition gear.
All I have to say on this one Is its all about amplifier quality and signal gain, Do you have an Equalizer/Crossover?
The audio control DQ components are great and only about $500,
That will Give you a good amount of signal boost to your Amplifier and will probably give that boost your searching for without using equalization. However I would recommend a subsonic filter set to 20-25 HZ as only your neighbors will be able to hear that wave and it will ease the job on your amplifier significantly
Also I am not sure of your budget or your subs but the older Zapco competition amps are way down in price well below $500, My Z350-C2sl I think is the name, something close pushes right about 350 watts a channel and does a phenomenal just phenomenal job on my 6.5" Midrange's
Those amps are great and ignore the rating i think my amp is rated at 30 watts x 4 but pushes about 85-90 RMS and bridged is pushing well over 300

Oh to the best of my knowledge you dont damage your hearing from low frequencies its the higher pitched frequencies that destroy your hearing, Please shoot back if im wrong id like to know.

High pitched frequencies can certainly hurt your hearing, perhaps at lower SPL than lower frequencies but SPL is SPL. They'll both do a number on your hearing.

And I love the guys that walk into audio shops and demand the biggest speakers that will do 20Hz. Dumb.