![Laughing :lol:](./images/smilies/icon_lol.gif)
Your engine draws more air than than your air con could keep up with, besides, thermodynamics would dictate that the energy consumed by the engine to run the air con compressor, would consume more power than would be gained by the reduction of intake air temperatures.
Whenever you convert energy from one state to another, you can never gain more energy out than has been put in, often converting energy from one form to another actually consumes a large percentage of the source energy, with just a small amount remaining in the second form.
Which is why electric cars, that you plug into a socket to charge, that is in turn fed by a national grid system, which in turn also looses energy, in turn fed from a coal or oil powered power station, is a complete oxymoron when referred to as green energy... Power stations do not have catalytic converters, much of the energy is lost in conversion and transportation, when it would be better for the environment to have a coal or oil powered car, and less of the fuel would be consumed in the same journeys.
Anyway, off the topic a bit....
So, if you have a source of cool air, it is better to duct that to the intake.
Sometimes in efficiency studies you can find a double wammy, such as a turbo, which turns wasted energy into partially recovered energy, or if you found a way of taking air, which otherwise would be an obstruction to the progress of your car, and use that for the cold air feed.
Many years ago I knew a chap who made racing motorcycles in the cafe racing days, he used to pass the engine oil into the frame of the motorcycle, so it acted as an oil tank (so saving weight) and acted as a large surface area oil cooler (also saving weight) all in one.. that is a good example of a double wammy.
Likewise, with a 996, you could in theory, duct air from your front bumper (restriction to the car moving through the air, partially reduced), which would be pressurized at speed (increasing your air intake slightly, a little like a turbo (just very small), duct it to your sills (airflow through the sills on a regular basis could actually keep them dry and so less likely to rust in time (although when driving through the rain it may be a different story) and then duct that to your air box (achieving the original goal)..
... but then again, that is a lot of work for a little gain, which, as funny how it goes, is exactly how often the way thermodynamics works as well..
(and before anyone else says it, of course energy is never really consumed, it just ends up in another form, when I say consumed, I mean that it has been converted into a format other than the desired format)