quick view Add to Cart Thermal Thermal R&D 2006-2011 Honda Civic Si - 3" - 4 Door - Catback Exhaust MSRP: $849.00 The Honda Civic Si exhaust is designed for maximum performance with a 3” catback design. Built from T304 Stainless Steel and a straight through muffler design, these systems will give you an... Add to Cart Add to Wish List Add to My Wish List Create New Wish List