I have a Sport Max with the Snorkel Kit and Honestly after a lot of looking and debating I did what others here have done and went to home depot and bought a 25GAL mobile tote, I installed it with stainless hardware and rubber seals. I have the wife and two kids with me most times and it works great for us and fits better that one would think. easy enough to remove if need be and its affordable be sure to remove the wheels,
id rather spend big money on a tuner or pipe maybe a clutch kit thats just me. see below link they do make a 50 Gal some guys have tried it but you will loose site out of your back window.
Keep all your gear secure in the garage or on jobsite using this Mobile Job Box designed by Husky. Comes with extendable metal tubular handle.www.homedepot.com