Manley forged and dished pistons for the 04-07 STI EJ257 are machined of high strength 2618 material. Each design is lightweight yet robust enough to deliver long service life. Round wire locks, tool steel wrist pins and piston rings are included with every set at no additional charge. A proprietary multi-step top ring groove machining process assures optimum control of the groove's size, geometry, flatness and finish. Precise pinhole machining results in an exact compression distance as well as precise lock ring groove spacing, size and concentricity. Manley pistons are available in standard size as well as a wide variety of oversize/overbore options to accommodate any high performance engine build.
All Manley pistons include a full set of four (4) pistons, piston rings and hardware.