xe pistons have a shallow dish and valve cut outs,let pistons have cut outs but with a deeper dish and a bulge in the middle.. early mahle xe pistons are forged but later ones are cast. xe pistons are best suited for a zvh engine. let pistons are forged and better suited for a zetec turbo as the compression will be lower. dont worry if you have xe ones ,there still good in a budget engine and will give a great torque of around the 300 lb mark