Induction with an Auto-Trans.

[Sweet Mercury]

I understand that it is inadvisable to put a turbocharger on a car with automatic transmission. My question is regarding and products which assist in a more effective passive induction. I remember years ago seeing a product that could be put into the intake which supposedly channeled air more effectively and got a little more "umph" out of the engine.

Of course, I can't remember the product's name, but I was hoping maybe you guys might know, or know of something similar?

I'm not a performance freak, but if I can spend a bit of money and get a little more something out of the engine it would be nice.

Or is any of these performance enhancers detrimental/warranty-voiding to my transmission?