I think that this is a great discussion.
To through something else in. When measuring the power output of a
engine it is always given as an estimate as the actual power is effected by several things including the current air temp, humidity and hight above sea level.
These facters also effect a N/A engine but much less
so. To have the most power from a
engine you want a nice cold humid day at sea level as this will give the maxium amount of oxygen in the air.
For a good example of this is the argentina rally which is run high up in the mountains and the WRC cars are well down on power to the point where the drivers complian.
The intercooler is ment to drop the temp of the air which does relase more O2 which (to my limited understanding) has combined with other elements at the high temps as well as reducing its volume.
Back to the original point and anything that causes the air to slow down (even on a N/A engine) is bad which is why you want any tubing/ducting to be as straight as possible and if you do need to bend it then nice flowing curves are best as once the air is draw in to the induction system it behaves like afluid and harp courners cause eddies and back flows which is why cone filters normaly give betterresults than pannel filters which don't always give the best air flow as they have to fit them in to the engine bay.