How are you playing these on your home system? With the empeg? If so, then EQ will still be a factor. Also, bass doesn't require much data... but high frequencies do. In fact, I think I remember svferris (a MusicMatch employee) saying that there isn't a setting in MM that has NO high frequency cut off.... I'm assuming that MM cuts the highes so it makes the LAME files sound overly bright. Who knows, it might even boost the bass curve?

I don't understand the file size thing tough... Can you post the file sizes of two compressions of the same song? And get the average bit rate too..?