I got a NAKAYAMA cai from ebay and it's awsome. I noticed that it lost a slight amount of low end tq but it gained so much on the top end. Before I had it I noticed that in 1st and 2nd gear my tq would drop right before I got to my red line however now my tq goes a few hundred above redline. And it made my shifts alot smoother. I haven't driven a car with a AEM but I would recomend my intake however there is a problem with installation.
When installing this intake the person that I got mine from didn't include instructions. And I would have blown my engine if I didn't know what I was doing and didn't have a little help from some guys on SHO. If you get this intake for a H23 hit me up for installation.
Peace