Manley 04+ WRX STi (EJ257) Size (STD) Stroke (79mm) Bore (99.50mm Grade A) SINGLE Piston w/ Rings

2618 Alloy Forgings: We use domestic 2618 alloy forgings, ensuring superior strength and performance.Chrome Moly Wrist Pins: Premium Chrome Moly wrist pins come standard with our Standard Series Pistons. For select SKUs, we offer wrist pin upgrades to 9310 and Turbo Tuff/DLC alloys, providing additional durability.Exacting Ring Lands and Grooves: We adhere to strict standards for piston ring lands and grooves, resulting in enhanced ring seal and more power.Cam and Barrel Profiles: Our pistons boast cam and barrel (skirt) profiles that generate substantial power while being gentle on cylinder walls.Unique Fixturing: Manley's unique fixturing allows for skirt turning and ring groove machining in a single operation, ensuring ultimate ring groove to skirt squareness.