Invidia Q300 Exhaust Honda Civic Si Sedan (2012-2013-2014-2015) HS12HC4G3S

Fitment Information

• Honda Civic Si Sedan FB6 K24Z7 9th Gen (2012, 2013, 2014, 2015) — Sedan only, does not fit Civic Si Coupe

Fitment Note: Civic Si Sedan only. The Coupe uses a different exit configuration and a separate Invidia Q300 SKU (HS12HC2G3S), which is also available on our site. Both require the K24Z7 2.4L engine. Non-Si Civic models and the 1.8L base engine are not compatible. 

Emissions Information

• This is a catback exhaust and does not alter, remove or replace any emissions equipment.

Specs & Features

• 70mm Exhaust Piping
• 110mm Exhaust Tip
• 304 Stainless Steel
• Direct Bolt On
• The Q300 is Invidia's quietest catback for the 9th gen Civic Si, using a twin-loop internal muffler design with Advantex material to optimize backpressure for a deep, sporty tone with minimal drone at highway speeds.
• If you want a louder sound level, Invidia's N1 is the next step up for this platform.
• Piping is 70mm (2.76-inch) mandrel-bent 304 stainless steel with a 110mm (4.33-inch) rolled polished stainless tip.
• A resonated mid pipe is included.
• Hangers are welded onto the OEM mounting locations for a direct fit.
• All hardware and gaskets needed for a complete installation are included.
• Backed by Invidia's 1-year limited warranty through us as an authorized Invidia dealer. .

Frequently Asked Questions

• Will this fit my Civic Si Coupe?
  No. The HS12HC4G3S is for the Si Sedan only. The Coupe uses a different rear bumper exit and needs the HS12HC2G3S instead. We carry both on our site so reach out if you have a Coupe and we will point you to the right listing.
• How loud is the Q300 compared to the N1?
  The Q300 is Invidia's quietest 9th gen Si catback. It uses a twin-loop muffler with Advantex material internally to control backpressure and keep the tone deep and refined. If you want more volume, the Invidia N1 is the next step up and is also available for this platform. Most Si owners describe the Q300 as sporty and noticeable but not obnoxious on long drives.
• Does this fit non-Si Civic models?
  No. The Q300 HS12HC4G3S is built specifically for the Si Sedan with the K24Z7 2.4L engine. The non-Si 9th gen Civic uses a 1.8L engine with different exhaust routing and this system will not fit those cars.
• Do I need a tune after installing the Q300?
  No. The Q300 is a catback system that does not touch the intake side or engine management. No tune is required after installation at stock engine configuration.

The Invidia Q300 Exhaust is one of the most innovative exhaust systems on the market. The Q300 features a specially designed flat bottom muffler that ensures high speed aerodynamics often overlooked by other exhaust manufactures. The Invidia muffler has continuous piping so the exhaust has free flow through the muffler, reducing backpressure and increasing horsepower and torque while producing the incredible sound that the Invidia Q300 exhaust is known for.

The Q300 utilizes SUS304 stainless steel that is one of the strongest on the market, and has a beautiful deep polish. All piping is mandrel bent for the best exhaust flow, and utilizes CNC machined flanges that are robot TIG welded to produce some of the best looking and strongest welds on the market. The Invidia Q300 is built to have outstanding durability and appearance.

Invidia Q300 Features

• Bolt on design - includes all necessary hardware for install
• Flat bottom design muffler for greater under body aerodynamics
• Free Flow Invidia Muffler
• Rich, Deep and Refined Sound
• SUS304 Polished Stainless Steel Mandrel Bent Piping
• Beautiful robot TIG welded exhaust flanges

Pairs well with:

• Skunk2 Cold Air Intake Honda Civic Si (2012-2015) 2.4L K24Z7 A cold air intake to complement the Q300 catback on the K24Z7 Si build. Skunk2 designed this intake in partnership with Compass360 Racing and it fits the K24Z7 directly without modification.
• BC Racing Coilovers Honda Civic (2012-2015) Civic Si (2012-2013) with Front Camber Plates A coilover kit to lower and improve the handling of the 9th gen Civic Si alongside the exhaust upgrade. BC Racing includes front camber plates with this kit which are useful for alignment correction after lowering.

OEM Part Numbers

• Rear Muffler Assembly, Civic Si Sedan K24Z7: Honda 18030-TR7-A11

This OEM part number applies to the rear muffler assembly on the 2012-2015 Civic Si Sedan with the K24Z7 engine.