well itr intake throttle body is if i'm not mistaken larger than ls, so thats why you would be better off putting the reduction from 3 to 2.5 since the pipe and the rubber fitting is 3'. Now there is not much diffrence between ITR aem and ls but ITR is 3' so most liklly you get a little more air thru it. think of this, why would they make 2 diffrent kinds of intakes ,if it they were preforming the same. Why waste money on making a 3' for a type r, integra is an integra right lol???????