Skunk2 Racing MegaPower Double Barrel Exhaust Honda Civic Sport Skunk2 Exhaust Honda Civic Si Sedan Coupe (17 21) 3" Catback w Double Skunk2 Racing SKUNK 413 05 6065 Skunk2 Mega Power Double Barrel (DB Skunk2 Mega Power Double Barrel Exhaust 2017 2021 Honda Civic Si Cou Skunk2 Racing Mega Power Double Barrel Exhaust System Honda Civic. The 76mm MegaPower Double Barrel (DB) exhaust system features 304 Stainless Steel, CNC Mandrel bent piping and robotically TIG welded joints for the highest strength and exhaust flow. Coupled with a minimally restrictive resonator and parallel, twin straight through race mufflers, this exhaust matches maximum performance with maximum style.