Thanks pelked1!!!

Just did this mod, and WOW! What an improvement you just saved me a lot of $$$ on a new stereo.

I used the 220uF non-polarized from Amazon (Parts Express), and the install took 10 min.

Then I rolled off the treble to my taste, -5 works for me. And all of a sudden, wow! There's midrange! And with it comes warmth, imaging, no distortion, and the annoying door rattle is gone! The piano and vocals on Evanescence My Immortal are stunning now, and the sub-harmonics on Bring me to my Life resonate the chest cavity without the door panels rattling and the speakers distorting!

I did roll of the sub a little ( -2), because it has tons of low bass. So I run Bass -2, Treble -5. vol about 30 most of the time and it sounds great. The stock setup had way too much mid-bass and treble, which sounds great in a showroom for 2 min, but leads to listening fatigue quite fast. The system now sounds far more accurate.

Thanks again, you have made my car so much more enjoyable.