JE Pistons Subaru EJ25 Ultra Series 99.50mm Bore Dia -16.5cc 8.5:1 - Piston SetDesigned for Power: Every feature on Ultra Series Pistons are optimized to perform high horsepower racing enginesAligned Grain Flow Technology: Exclusively available on JE Ultra Series, this proprietary, in house forging process maximizes tensile strength to withstand the stresses of high performance engine environmentsSkirt Coating: Reduces friction and wear on piston skirts and cylinder walls while simultaneously reducing operating noise, especially