Use this piston set when you want to upgrade your 2002 - 2005 Subaru Impreza WRX or 2005 Saab 9 - 2X Aero engine for better performance. It's perfect for car enthusiasts and mechanics who want to enhance engine power. The pistons have a 79mm +4mm stroker and 93mm +1mm bore with an 8.5:1 dish design.