I feel a little "lag" until it's about 3000 rpms and especially after 3500ish it opens up really good.. It only bothers me when I go half throttle or on a ramp. The oem torque converter gets the car going around 2000-2500 anyways so the 500-1000 rpms in between doesn't really last long.. I think the oem headers are 2.0 - 2.25" in diameter and Strups (as well as Stillens) should be either 2.5" or 2.75". That should be the reason for the low end lag.. Nismo headers take care of that by decreasingly sized tubings.. They should be 2.5" right out of the ports and 2.25" or 2.0" when closer to the flange..
Psiclne's loss should me more as he's using the 3.0" Nismos.. Larger D headers + larger D exhaust = awesome sound + sluggish low end torque.. He should really feel the torque around 4000-4500 I believe. With stock exhaust + headers you should get it around 3000-3500 like I do.. Basically the torque curve should shift 500 rpms per .25 " increase in diameter.. Correct me if I'm wrong..
