Warm Air Intake System -- Heater coil or core?

[rh77]

I'm tweaking the temperature of the air coming into the vehicle's intake and I can't decide what to do as winter is approaching.

We know air is a poor conductor of heat, so what to do?

*Draw air from the catalytic converter, but it's a ways away from the destination, so temps (especially on cold days) would possibly be robbed.

*Get a heater core and fabricate a box close to the intake. (I don't want a junk one because who knows what crud is in there, so a buy a small, new one)?

*Would a small intercooler (like on the top of Subaru's turbo engines under the hood scoop) work? I'm afraid that the coolant would be to caustic for a device designed for air only.

*Somehow electrically generate the heat. A cigarette lighter makes a bunch of heat -- maybe on that prinicple. like wrap a wire around a metal pipe and use the car's electrical current to somehow draw heat that way?

Any ideas would be appreciated...thanks...

RH77