I have both the TRD exhaust and CAI. I love the combination. As others have said, much deeper tone but not too loud. I put it on the dyno, unfortunately did not have it dyno'd stock so not sure about actual performance gains but I will say it made a noticeable difference. See the Video here: [ame="http://www.youtube.com/watch?v=slDSe4drTUo"]Dyno - YouTube[/ame]
It's hard to hear with the dyno noise and fans until about 38 sec's in when he gets the RPM's up....I have pictures of the new and old exhaust and intakes in my photos here:
http://www.ft86club.com/forums/album.php?albumid=718.
The CAI was only in 5 days before the dyno so I don't think the ECU really had time to settle in, felt a difference initially but it kept getting better for at least a week after the dyno.... The easiest way to describe the difference in the car is like driving aggressively with the AC on then again with the AC off, it's a little better than that but its close....
Dyno sheet Here:
http://www.ft86club.com/forums/album.php?albumid=802
Enjoy!!