one question for you...why are you so bent on improving the SQ of an MP3? if they are ripped at 128 they are going to sound like 128, ripped at 320, will sound like 320. There really isn't MUCH that can be done in this aspect. This is where you need to have a stereo system that is built to adequately reproduce your music. You can have something recoreded in the best possible format, but if you system can't reporduce that, then there's no point in the other.
Again, you are aking aboutthe knobs, and I'm answering (again) with the alpine unit like what I am running in my car.
You say you want good sound quality, yet you don't ever go much further than treble and bass. there is SOOOOOOOOOOOOOOO much more to sound that trebble and bass. Those two paramaters (if you will) are just the outter edges of what can be tweaked and controlled with sound. For instance, the alpine unit I speak of has a total of something like 171 bands of equalization....that's way above and bayong your simple treble and bass settings
settings so simple will never do much to improve SQ IMO
EDIT: more of a PS if you will....
I'm not running any sort of correction on the software side of things in my car and I'm still winning sound quality shows. Granted, I'm not running MP3s at these shows, rather a CD as that's what the rules state, but you still get my point. software is NOTHING without a good stereo to back it up in this instance.