As others have said, the only real solution is a solid rear window. I had a buddy in HS that solved the problem by tinting the hell out of the window then deadening the hell out of the window then using foam to silence the rattles....it still rattled when we put two decent 12's in it and he lost almost all use of his rear view (of course, I dont have a rear view because it finally got rattled off). I love my solid rear window. 3 layers of second skin and there's no rattles coming from the back wall short of when the back wall flexes enough to hit the plastic bedliner and by then the bass is so loud SQ doesn't matter and you can hardly hear the rattle anyway because of the bass and the screaming because of the passenger's ears hurting so much. lol
2000 Mazda B3000 TL Edition 2wd
-Gibson Exhaust- -Gangsta' Tint- -31" A/T's- -2 15" SI Mags- -Sundown SAZ-1500D- -LSD- -Torsion Bars Maxed-
*Eventually: Head Lights, More Tint, 5.0 swap, Murdered, Tube Bumpers, Off Road Lights, Body Lift, Better Stereo, More...