I'm trying to buy an auxilary fuel tank for my Ford F250 Diesel. Local mechanic said that they aren't allowed to plumb them into the existing fuel tank anymore. Has anyone else heard this? Also, the cost of the auxilary tank is beyond belief. $600? $700? Up to $1000 for the tank/tool box combo unit. Am I crazy? Or, did I used to buy a 100 gallon auxilary tank for about $125 and then add a little labor have a guy plumb it in? Help!!!!!!