JE Pistons SUB STI EJ257 Block w/ EJ20 Head 99.5mm Bore CR 8.5 KIT Set of 4 Pistons - 291059

Forged in the USA using 2618 aluminum, yielding high tensile strength needed for high-demand performance applicationsDesigned specifically for each engine and use application to provide optimized performance durabilityProprietary Forged Side Relief (FSR) forging design minimizes friction and power loss with reduced skirt width and saves additional weight with a shorter wrist pinSkirt coating (depending on application) reduces friction and wear on piston skirts and cylinder walls while simultaneously reducing operating noiseAccumulator groove (depending on application) helps reduce pressure from combustion gases, reducing ring fluttering and improving ring seal for consistent powerIncludes high-quality wrist pins, locks, and JE Pro Seal premium piston ringsMade 100% in the USA