Gravity Performance decats instantly increase power by allowing exhaust gasses to exit the vehicle quicker. Our decats are designed to be direct replacements for the OEM catalytic converter, ensuring smooth installation every time. ---Manufactured from high quality T304 grade stainless steel ---Free flowing catalyst replacement to get the most from the EJ20 and EJ25 boxer engines ---Designed to fit the original and most aftermarket exhaust systems ---3" bore tapering down to 2.5" at the outlet ---Sold for off road and track use only Fitment --- Subaru Newage WRX STi 2001-2007 models.