This online retailer sells the kit for $249/$199 w/o hose. He used to sell Champion 3100 with the kit already installed(I got one of them). Looks like he no longer does.
http://www.bottomlinetrading.com/Champion-Inverters.htmlthe kit comes with fuel pump, fittings, hose, etc to connect external tank. does require some basic skills to install the fuel pump permanently. Works great. Internal tank is still functional too, the switch is the fuel on/off. Fuel on = internal tank, fuel off = external tank. Looks like factory install when completed.
Dave
2016 F350 Lariat 4x4 FX4 SRW CC SB 6.7 Magnetic Metallic
2017 Forest River Cardinal 3850RL