I pulled the intake resonator off of the stock airbox today (bottom tube). Sounded exactly the same as before until I gunned it. Man oh man, for something that takes all of about 30 seconds to do... what a difference. This car sounds MEAN. I'd say this is totally worth it for the sound alone. I do plan on getting a CAI eventually so I'm not sucking in hot air, but really, this is what your car should have sounded like from the factory.
I haven't really noticed any changes in terms of engine responsiveness, but I took the car through a tunnel tonight with the windows open... pure madness.
I love this car so much.
No pics yet, but it looks similar to the following:
