Custom tuning works to give better performance because it changes the way the ECM translates input from the sensors for peak performance, not emissions, just like the old Trans-go kits modified the tranny valve bodies for maximum shift performance not comfort or gas mileage. But adding crap to boost air or gasoline feed to get a greater explosion and increase horsepower without a change in tuning won't because the ECM will follow its native algorithms to compensate for and defeat the attempts.
Both intakes are before the restrictive air filter. The air box draws air from the fender well, not the warmer engine compartment and given that size opening compared with the much smaller opening on a ground suction CAI system coupled with resistance in the snorkel's convoluted duct produces little if any increase in airflow....any excess pressure from a ram effect will sooner blow out the much larger air box opening into the fender, just like the dreaded water entry, instead of through the restrictive air filter.
And there is another reason why you do not want incoming air too cold. Heated air intakes were not designed only to decrease emissions but to also combat icing in the induction system caused by a venturi effect at the throat of the carb or throttle body.....a forward facing air intake to force in moisture from rain or snow might not be a such great idea under those conditions.
The Avy isn't governed by concepts in theoretical physics, it's ECM brain is more concerned with strict adherence to EPA dictates than giving owners' peak performance, and it isn't easily tricked by gizmos trying to mess with its brain......aside from the MAF sensor assembly which also contains an integral temperature sensor to compensate for both air volume and temperature, other sensors constantly feed in to defeat any screwing around from what its factory algorithm considers an ideal mix......even if you could fool it and increase the density of the air mass in the combustion chamber that will increase the compression ratio and the knock sensors which set the spark advance to just the point to prevent preignition which is a function of the compression ratio, will detect a knock and it will tell the ECM to retard the spark or change the valve timing on VVT engines and down goes the effective hp boost.
At 320 hp with a 6 spd. and 3.42 rear which is equivalent to an effective 4:13 ratio in 1st on a 4 spd.. there is more than enough power to get off a start and move my ass from point A to B........If I want to feel more horsepower in my Avys from add on crap, short of a custom tune which would void the warranty, I'll mount baseball cards to flap against the wheel spokes which in my opinion is much cheaper, a lot less work and just as effective...if I want to race some A-hole in the street, I'll garage the Avys and Malibu and buy another Camaro or a Vette.