After scouring the forums, I couldn't find much on fixing the sub rattle other than dynamat. Today I remembered an old trick that worked on my old maxima, rubber washers. You simply unscrew the sub, slip some 1/8th inch thick rubber washers under the four screw holes in the sub, and put the screws back in. Rattle completely gone! For me and my '02, anyway. Good luck!

 

I guess if you screw down tight enough, it should seal still...good idea sir!

 

I tried this and it didnt work. There is still rattling in the back, even with the radio off.