Make sure you don't just compare the peak numbers when looking at this. The thing people seem to forget is that you feel the torque when you drive. That gives you the sensation that most associate with a fast vehicle. If headers only give you 2rwtq at peak, but they give 30rwtq or more across some portion of the RPM range, you are gaining much more than headers that give you 30rwtq at peak but only 2rwtq across most of the RPM range. For those who love math, AREA under the torque curve is what counts and not the peak number.
This is a lot of the reason why a long tube header will pretty much always outperform a mid to short length header. The long primary of long headers allows for a proper scaveging effect to take place, thus helping the cylinder pull the next charge in. Although this is typically confined to a limited portion of the RPM range, the added 'seperate' volume of each primary allows that cylinder better flow during the entire RPM range.