Be careful.. at full rear shock compression these type boxes will shear off your mud guard mounting bolt and could take out your rear brake bleader... ask me how I know
edit: to be fair to advdave, who just sent me an email, I am not sure if the damage to my rear brake bleader was caused by his box, or the european manufactured one I replaced it with. I had one of the early versions of advdave's box, but sold it pretty quickly because I did not like the side opening design. I replaced it with one of the rear opening boxes from ebay. I honestly do not know when the damage occured. Dave says his boxes have a cut out on the backside specifically to avoid the brake bleader, so I imagine the damage was done by the newer box. Also, I have a bad habit of getting both wheels of the GSA off the ground on occasion.. so I may be compressing the rear shock more than most. I will check the new box when I get home and see what they have done on the back side to address the rear brake bleader and will post up what I found... could be that Dave has a better design because he has thought of the bleader.