The Skunk2 intake manifold seems to be worth about 6 to 7rwhp vs. the VICS  with our build with torque dropping slighting at 4000, but increasing at 4500 rpm and beyond.

VICS vs. Skunk2

Moving from the stock JDM VICS manifold (Not square top) to the Skunk2 resulted in trading torque at different RPM ranges.  Torque differentials would likely diverge more in higher RPM ranges, but for endurance race applications shift points are relatively low.

BLUE – Skunk2 (Muffler) – More Torque after 6250

RED – Skunk2 (No Muffler)

GREEN – VICS (Muffler) – More Torque 4200-4700

Skunk2 vs. Squaretop

In an effort to eliminate the torque hole that appeared at ~4200 RPM, I purchased a squaretop manifold and went to the dyno.

BLUE:  Squaretop Manifold
RED:  Skunk2 Manifold.

In short the manifolds perform almost the same, except the Skunk2 actually has better torque performance in the area were were trying to optimize.