A properly designed exhaust system is critical to engine performance. Skunk2's 70mm MegaPower Exhaust system for the 02-05 Civic Si was developed with this in mind and is based off of more than 15 years worth of racing experience. Dyno-proven for maximum horsepower, MegaPower R cat-back systems are constructed of T-304 stainless steel, are robotically TIG welded, and feature CNC mandrel bends for a precise fit. Designed for naturally aspirated engines featuring higher compression, aggressive camshafts, and racing headers as well as for mild turbocharged applications that require more exhaust flow than Skunk2's 60mm MegaPower Exhausts provide, MegaPower R Exhausts allow engines to breathe more efficiently and produce more power thanks to larger diameter piping. MegaPower R Exhaust systems were designed for maximum flow and power, featuring oversized tubing and mufflers, which results in a significantly louder tone when compared to 60mm MegaPower systems. Featuring Japanese-spec, Super N1 styling, MegaPower R Exhaust systems generate more horsepower by optimizing engine airflow and volume through carefully selected, application-specific tubing lengths and diameters and increased wave scavenging effects for more horsepower. CNC mandrel bending allows for a constant tubing diameter throughout the bend, which results in precise fitment as well as improved exhaust gas flow. Each system is fitted with a resonator, includes stainless steel flanges, and is finished off with a straight-through, low-restriction racing muffler for uninterrupted flow. Each fully polished muffler is mated to a 110mm polished tip with its own acid-etched MegaPower badge and serialized nameplate. A Skunk2 removable silencer and all necessary hardware are also included. Skunk2's MegaPower Exhaust lineup is based off of the same systems we custom build for our road racing and time attack vehicles.