HEAD GASKET EJ20# GC8/GDB JDM/EJ20# 02-05 WRX USDM 93.5-1.5mm by Tomei

The factory type is made from metal but the design is the bead type which is not as effective in sealing as the super grommet design. Most aftermarket metal gaskets are of the grommet design which is better but the TOMEI Super Grommet design gives you the highest sealing efficiency possible and increased durability.(Super Grommet=Dual Sealing System from bead structure and metal grommet)? Custom Rib Design (Improved Seal Around the Water Gallerie) With each model change from Subaru engineers the improved engine design from the GC8 to GDB and A models had the increased the rib of the outer bore diameter which improved the gas sealing characteristics. But the results of that change made the water and oil galleries seal decrease. So when the power is increased there is also the increased possibility for oil and water leaks to occur. TOMEI engineers has a second look at the design of the rib height and the Super Grommet Design and Tomei have achieved an overall improvement in overall seal.? Various Sizes AvailableTomei had made 2 types of thickness available for the better option for you to achieve your desired compression ratio for your application. Now you can build an engine with higher accuracy to suit your needs.TOMEI Metal Head Gasket Since cylinder capacity can be adjusted by changing the thickness of the head gasket, a thicker head gasket can be used to increase your's engines compression ratio. Alternativly, you can choose a thinner head gasket and maintain your's stock compression ratio. The stainless material used for the TOMEI Metal Head Gasket was chosen for its high heat capacity, because stainless material dissipates heat at such a high rate, you greatly reduce the risk of head gasket failure.