Greatly reduces the transfer of heat from engine to intake manifold thus reducing heat soak.

One of a kind true Phenolic material, not cutting board material like others.

The cooler your intake temperature is the denser the air is which leads to more power

For every 5 degree reduction in temperature, increases power by 1%.

The cooler and denser the intake air that the engine sucks in, increases the amount of air that can be mixed with fuel thus increasing efficiency.

Direct bolt-on.

When running the oem gasket only, your intake manifold gets very hot to the touch, enough to burn your hand. When the oem gasket is replaced with GrimmSpeed's Phenolic Spacer, your hand can be placed on the intake manifold without any issues.

GrimmSpeed has installed both with and without OEM Subaru Gaskets and have had no issues with either way.They do recommend using 2 sets of oem gaskets however, one on both sides of the spacer.

USA made