CP 99.5mm Bore 9.0:1 Piston Set 2006-2014 WRX / 2004-2021 STI / 2005-2009 LGT / 2004-2010 FXT
The piston is the weak link in the stock STI block. These are great for someone either reassembling a their block or someone looking to put in some strong pistons in their "built" block.
Throw these forged high strength aluminum pistons in and turn up the boost and get more power from your STI! These CP pistons have been put through rigorous testing. In short, they are build to withstand nearly whatever you can throw at em'!