I first bought a Dinan CAI. I loved it, it sounded amazing. Then I got the uuc system u, and I can't hear my dinan at all anymore.
If you get an aftermarket exhaust with any loudness to it at all, it doesn't matter what kind of intake you have. haha. Beware of the system u though. It has an amazing sound and is nice and deep... however it's VERY loud. If you're trying to be quiet in a neighborhood at 1am, it's impossible. An example is yesterday morning I was leaving at 9am and Natalie (nattles on the forum) was sleeping over at a friend's house next door. She said I woke her up when I left, and I didn't go above 15 miles per hour (i try to keep the sound down in neighborhoods). On the other hand though, if you want to show off on the freeway or something, and you punch it, EVERYONE notices. haha. Even if you're driving alone normally in town, everyone turns and looks when you drive by.