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

If you're rebuilding the engine in your 2004-2014 Subaru WRX STI with the EJ257 engine, these Manley Performance pistons are a solid choice. They are designed as a direct replacement for the stock bore size, measuring 99.50mm, and feature a standard 79mm stroke. These aren't just generic pistons; they are forged from 2618 alloy, a material known for its strength and ability to handle higher performance demands compared to cast aluminum.

Manley puts a lot of thought into how these pistons work inside the cylinder. They use proven cam and barrel skirt profiles, which help reduce friction and wear on your cylinder walls while still allowing the piston to generate power. The ring lands and grooves are machined to very precise standards, which is crucial for getting a good seal with your piston rings. This improved ring seal means better compression and more efficient power delivery. They also come with chrome moly wrist pins, which are strong and durable for this application.

These pistons are a popular choice among engine builders because of their well-built construction and the attention to detail in their design. They are made in the USA and are a significant step up from stock, offering the durability needed for modified or performance-oriented EJ257 engines.