HKS Legamax Premium Cat-Back Exhaust - 2017+ Honda Civic Hatchback (hks31021-AH004)

Regular price $1,320.00 USD $1,002.75 USD

In Stock. Pre-order.

Ships in 10+ weeks

Part # hks31021-AH004

About This Item

Legamax Premium mufflers offer the performance benefits of a sports muffler with the class and elegance of a premium muffler. Every tailpipe design is customized per application to ensure that the muffler has impact and becomes a focal point in the appearance of the vehicle, yet blends with the overall design of the car. Legamax Premium mufflers are constructed of SUS304 grade stainless steel to give a high luster finish that is durable. The new 2017+ Civic Hatchback application comes with titanium dual tips. It was designed to be as straight as possible providing a 50% reduction in exhaust back-pressure to support more power modifications.


  • This product was previously released as 31021-BH002 Since the fitment to the JDM model was confirmed, the part number was changed to 31021-AH004. Also, this product is designed based on JDM and USDM models. Please confirm the model available in your country before purchase.
  • Civic Hatchback only with 1.5L Engine


  • Honda Civic [FK7 - Hatchback non Type R] (2017, 2018, 2019, 2020, 2021)


Full straight structure to improve exhaust flow
Tested and JASMA approved
Made of high-quality SUS304 for durability
Back-pressure reduced by 50%
Meets a standard for Japan's noise level regulation
Cat-back system includes Midpipe
Center exit design with dual titanium tips
Designed to eliminate exhaust drone
Made in Japan


Type: Cat-Back Exhaust
Piping Diameter: 60mm to dual 50mm
Tip Diameter: Dual 97mm
Material: SUS304 Stainless Steel Piping
Chassis Codes: FK7
Engine Code: L15B
Idle Sound: 61 dB (stock 53 dB)
Sound: 87 dB (stock 80 dB)
Pieces: 3-Piece System
Notes: 5mm less ground clearance than OEM
Warranty: Manufactures Warranty

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Return & Cancelation Policy

In stock, non special order items can be returned within 30 days of the product arriving to your house or place of work.
Returns will NOT be accepted on final sales, special orders, opened, installed, incomplete, or otherwise used products. In order to initiate a return, an RMA number must be requested and approved via e-mail.
All returns will be subject to a 20% restocking fee minus complete shipping cost (roundtrip).

Any processed orders that have not shipped will incur a 6% cancelation refund fee unless the product was not available to ship within a timely manner. No fee will be incurred if used as store credit.

For complete details on our return policy, please see our Help and FAQ link under HELPFUL INFO.