Hey all,
Well I parted with the whole buck's for this diode for my Aveo. And you know what, it does work or at least does something. This is what I have found so far.
-Exhaust tone is a bit lower at idle
-When you are going through the gears the engine RPM drops MUCH faster
-I had a kind of "Tuner car" popping on decel- it is gone
-Faster acel under lugging, too low of a gear selection as well as faster response
-So far I have used a bit less fuel for the K's I have driven
-When you open it up you can hear the CAI, it is MUCH louder

I do not know if all this adds up to more performance. It is for sure different. I will keep you up to date as time goes.
I also put one in my Cavalier. It is an auto and it downshifts way sooner than before when pushing the throttle. And the CAI is much louder.