Why not just do a smart controller for the intake heater?
You could use an Arduino (
http://www.arduino.cc/) and program it to turn on a FET to run the heater on key one events.
Then turn the heater off or reduce power via PWM during the start/cranking event. You could use 4 FET's and setup an H-bridge controller and feed the heater an AC square wave and even measure the intake temperature based on the heater's impedance feeding it more power at key on and tapering off as it gets to peak temp.
Arduino's range from $10 for the mini to over $60 for the really big ones.
FET's range from under $1 to maybe $4 a piece. You only need four for the H-bridge.
Then a handful of random resistors and caps.
Not counting connectors were talking way under $30.
Connectors can get expensive. But thats still only a few bucks each and you maybe need 2 or 3 sets(female + male).
-Avery