I've been running dual tanks with the all the Ford parts for my 2nd, the rear ford tank, dual tank selector, and cab flip switch for 8 month's. I T into the stock evap system and haven't thrown any codes. I'm running the Toyota fuel gauge off the Ford switch which automatically switches between tanks, so no need to add a 2nd gauge. I ran a separate fill point to my rear bumper (the bumper offers far more protection then the stock front tank fill position) u just have to make sure the fill point is higher then the tank. I did cut and weld all the Toyota tank fittings so I could use all the stock runner parts, plus the Toyota fill port has the safety flap in case you roll... the only issue ive have is bumping the cab switch with my knee when 4x4, the ford selector works by switch from + and -, when the switch is partially engaged all the gauges will start dropping out and on as they would normal with a bad ground so make sure switch is full engaged.