I think you will find that the minute you go over 350L it puts a lot of underwriters off the list , also madness i know but if a tank is bolted it is classed as a mod , if strapped and easily removed its not a mod , its all red tape and cash cows as most will be using more than a 350 L and they know this as fact , hence why i use a 350 and have it strapped to a removable frame that is bolted to the original eye loading anchor points , therefore no mod to the original chassis has occured .
Looks like i found the loopholes by pure chance !