Dynamat the tub. I installed mine on the backside of the rear mat on a past d90 because I didnt want to stick it to the tub directly. Worked pretty well.
Bolt on bits makes a corner guard to go over the side of the seat box.
YRM 2001 as wellYou have a link? I cant find anything on their site
I researched spray on sound deadeners and they all need to covered with some sort of mat or carpet if you are going to carry heavy stuff in back. Its a softer compound than a bed liner type material and won't take much abuse. You can apply a bed liner or paint on top of spray on deadener after it cures. I used Second Skin Spectrum and it works pretty well.