I had a AEM SRI on my car.. (its now in my trunk.. ) but its not as bad as everyone makes it out to be.. your engine isnt going to bog down.. or anything like that.. It would just lose power.. its just that the only time you will see a real difference between it and stock is when the engine is cool.. after that there isnt going to be much improvement because its sucking in hot air..
The thought process is that it doesnt take much suction to bring air in from a SRI, so the resistance is less.. the downfall is that its suction is sucking in warm air.. which is less dense and therefore you get less actual combustible air in the chamber.. Which is the purpose of the CAI, it brings in cooler air, so that you have more air, which means it burns fuel more efficiently.. which means more power..
although its a small amount, sucking air from way down in the fender well has more resistance than from doing it from the SRI..
BUT.. I think the CAI is better just thinking because although it has to use more energy sucking air.. it should make up for that by burning better..
Not to mention that I have tried both.. and I like the sound of the CAI better, (its not just a growl) and I think there is more power, especially top end power.
But I'm no expert..
