[beer]

I agree that a warm intake could help with better MPG, BUT not with lean-burn honda engines!
With these engines you want to stay as much as possible in de lean-burn mode, and the ecu gives the leanburn signal according to engine sensor parameters, one off these is the TPS-sensor (Throttle Position Sensor), which the ecu sees has a signal how much load you give it. (TPS 32%)
Has you know the leanburn mode works only with light load .
With a warm intake you give more throttle, thus give a higher TPS signal, which will deactivate the lean-burn mode.
So with a honda lean-burn engine you better off making the intake temperature as cold as possible, so it stays a longer period in the lean-burn mode. (and reduce throttle losses, which is what you wanted to accomplish with the warm intake).

But this only applies to a certen point, becouse if the oil en general block temperatuur in winter don't become hot enough then the engine starts to enrich and is better of with a bit warmer intake to fool the other sensors and cut the enrichment. (till about 5 degrees celcius)