Subaru WRX STI 2.5 EJ257 Wiseco pistons 99.75mm CR 9.0 K598M9975AP

Armor Plated wiseco pistons have almost a bronze colored tint to the top of the piston and the wrist pin bore. Wiseco’s Armor Plating is an abrasion resistant plating that raises the hardness of the aluminum, increases the durability of the ring grooves, prevents micro-welding of the piston rings, reduces carbon buildup and combats corrosion caused by detonation. Wiseco’s most popular pistons now include Armor Plating.