What works for me/Stereo
To each his own when it comes to what sounds good is my saying. Although my GTO stereo will never sound great this is what I have done in the week I have had my car. DDL off, Loc on, treble on 5, bass on 3, and amp in truck just a notch from the most negative end. With the amp turned down I eliminate the rumble, which is really not true bass. This to me is the best I can get. Funny thing. I have had everything from BMW M3's to Mazda RX8's, in the past several years and here is what I have found. When you are buying a car and you find that a car has a Blaupunkt, Harman Kardon, or Bose to name a few, run the other way. There is a good chance that it will sound like crap. I have experienced this with BMW (Harmon Kardon), RX8 (Bose) and GTO (Blaupunkt). I just rented a Grand Prix for a vacation trip and stereo sounded great. It was factory and none of the brands mentioned. That is my two cents. My Sirius satellite makes it sound a bit better on a side note.