Circuit Spec Exhaust System

The system utilizes 2.5-inch brushed stainless steel piping and flanges, paired with a polished stainless steel muffler that terminates in a 4-inch tip. This design aims to provide a louder and more aggressive exhaust note. Specifically engineered for OBD1 and OBD2 1.8L NA Miata models, this exhaust system includes a secondary O2 bung for sensor compatibility. ISR Performance explicitly states that this Circuit Spec listing is for the 1.8L engines; 1.6L Miata owners should refer to the separate 1.6L Circuit Spec listing. The mid and tail sections are standard, with no variations available.