[Magician]

I put a warm Air intake... fully insulated the tubing from near the exhaust manifold all the way to the intake manifold. I even insulated the filter housing so the warm air isn't cooled along the way to the intake. This has made the warm air intake much more effective than without being insulated and my mpg's have gone up significantly for winter mpg's. I'm getting much closer to Summer MPG's! Typical Winter economy was 44mpg and Summer was 54MPG.
Now my Winter has been around 48-50MPG since mod with insulation.
BTW, I used insulation that is high temp... used for insulating your home water heater. Have R value of 7 I believe and 250 degree rating. As long as you keep it 6" away from the exhaust manifold, you are golden.