When building a high horsepower 2011-14 STi 2.5L EJ257, the stock engine pistons have their limitations. Pistons take an extreme amount of abuse with very quick directional changes and extreme g-force loads, so it's crucial to upgrade the stock pistons to forged pistons when engine upgrades exceed basic bolt-ons. We carry only the highest quality pistons from CP Pistons, Manley, Cosworth & Wiseco. Pistons are available in standard sizes (stock bore) as well as a wide variety of oversize/overbore options to accommodate any high performance engine build. If you have any questions about the pistons that we carry or can't find what your looking for, then please contact us.