I left the original electric heating element in it for low temps, like drying jerky, and I also drilled a hole through the side, mounted a Barbque control valve on the outside wall and then mounted a Nat Gas Barbque burner inside just above the electric unit.
When I do Jerky, I turn on the electric unit and fire the gas burner and do 1 pan of wood chips, then shut it off and continue with the electric element untill the jerky is done.
For smoking meat, I use the gas burner as I need the added heat that the electric unit dosn't produce, with what smoking I have done, I keep the heat around 220 degrees which dosn't seem to be to hot for the electric stuff. I have had temps as hot as 200 degrees with the electric unit, but on a cold damp day here in the Pac. N.W. its hard to maintain a good high temp using the electric unit, so that is why I installed the gas burner.
One really neet thing about the food warmer, it has the shelf cleats all up both sides, I bought grill racks at Home DePot and cut to fit for my jerky and laying meat on for smoke, and I use wooden dowels resting on them cleats for hanging my pepperoni on.
Will take pictures of the lower part showing the burner and post real soon.