JE Pistons Subaru EJ25 Ultra Series 99.50mm Bore Dia -16.5cc 8.5:1 - Piston SetJE Pistons Ultra Series pistons for sport compact and euro applications combine all of the best, most desirable piston features, such as thermal barrier crown coating, lateral gas ports, thick wall wrist pins, and a revolutionary new forging technology for the ultimate in strength. Premium, gas nitrided carbon steel rings are included.