I've always kind of been skeptical of the dynos on headers. Due to the layout, you might be able to squeeze a few hp more here or there or tune the torque band by the collector placement, but most NSX headers make around 20-25 more than the stock iron manifolds. I think the outliers (both above and below this range) are due to the dyno, car, tune, other mods, air temp, etc. I would imagine these Revolution headers are right around the 20-25 mark like all the other quality NSX headers.