Fitment Information Honda Civic Si Sedan (2017, 2018, 2019, 2020, 2021) Specs & Features Chassis: FC3 coupe  Engine: Turbocharged L15B Type: large diameter Cat-back exhaust Number of pieces: 3pcs Piping: 76 mm (3.0 ") Tips: 2x 105 mm (4.1 ") Gasket(s): 3.0 " oval (qty: 2 included) replacement Resonator: Yes Weight: TBA Sound level: TBA dB(a) The unique dual muffler Supreme SP for the 10th generation Honda (FC3) Civic Si coupe features high-flow with a refined exhaust note. Under wide-open-throttle, spirited driving, the system offers the classic GReddy deep exhaust growl. To enhance the performance of the turbocharged 1.5L engine, this 3piece, full cat-back exhaust connects to the factory downpipe and expands to large 3” (76mm) front-pipe and mid-pipe that split to two polished, straight-through SP oval mufflers and dual center-exit dual-wall GReddy tips. This tip and muffler combination is a great compliment to the Si’s sporty, but wide rear bumper tip opening. (We also offer a similar, application-specific system for the (FC1) Civic Si sedan.) Like all GReddy Supreme SP systems, the fully hand-welded 304 Stainless-Steel exhausts carry a Limited Lifetime Warranty. The legacy of the GReddy SP lives on with GReddy’s best version yet, the Supreme SP and to prove it carries a limited lifetime warranty! From the 1st flange to the new double-wall GReddy Tip, each Supreme SP system features a high-quality, hand Tig-weld 304 stainless-steel outer construction. Within the muffler, new straight-through and directed- straight-though chambered muffler designs allow GReddy to engineer a more refine exhaust note while increasing exhaust flow and performance. Classic GReddy street performance styling is maintained with excellent fitment and a stylish exhaust system layout. The Supreme SP not only designed to perform and sound great for each specific application; it matches the vehicle’s body-lines and styling. Redline360 sells only genuine and authentic GReddy products.