I don't know why the lean, but the kid that installed my Snug lid says ever one that he has seen does it. Some are over an inch difference.
I know exactly what your talking about on the time to clean the glue off. I'll try to find one of the 3M wheels tomorrow. I ran so much today that I didn't have time to look for one.
I'm not sure what the options are for adding more bass. Take a look over at
www.fullsizechevy.com in the audio forum and you will probably get more info than you can stand.
I have been looking at adding Sirius radio. I have it in my Dodge QC truck and like the comedy channels. I just hate paying a monthly fee. I got a free radio and lifetime subscription when I bought my Dodge so I'm spoiled.