GK: thanks for the non-judgemental post.

Even though the ITR is a good bit different than the GSR, they're both B-series motors. It's well documented that ITRs make huge gains with proper exhaust setups and good tuning. But as you noted, the motor has a lot of incremental improvements that when added up, create somewhat of a need for the extra exhaust flow such that opening that end of things up makes the extra hp. It's not totally irrelevant and as Trey pointed out, a 2.5" header can make power on a lesser B-series motor. Just that the gains are not going to be as consistently impressive as what's seen on an ITR.

The overall point of my post which has been "disagreed" with was that the original poster should in fact do exactly what the "dissenters" say. There is no need for certain folks to "disagree" for purposes of yet another theoretical debate that derails a thread.

If people want to debate general theories and principles on any one particular aspect of tuning, they should make a thead about it instead of derailing a thread that asks a specific question about a specific car. That is all.