Thank you, oh voices of reason.
Unfortunately, none of these options include toggle switches. That just won't do.
Im using a modified intake with a cone filter, and I do agree that the best option is using exhaust heat...
However, first of all I can't switch it on or off like I can a glow plug. Also, I want to keep a short ram intake design, I want to avoid the power losses that come from snaking an intake hose all around the engine bay. The way I have it now its almost a straight shot.
A heater core would work well although I fear it is too restrictive on the air flow, and also a bit more troublesome to adapt to an intake pipe than just drilling a hole in the side to insert a plug.