APR Catback Exhaust System - S4 / S5 (B9) - CBK0012

Designed for enthusiasts seeking the perfect balance of power, sound, style, and quality, the APR Catback Exhaust System for the Audi B9 S4 and S5 is a testament to engineering excellence. With its performance-driven design and durable construction, this system not only transforms your driving experience but also ensures years of reliable performance.

This Part Fits:

Year	Make	Model	Submodel	Notes
2018	Audi	S4
2019	Audi	S4
2020	Audi	S4
2021	Audi	S4
2022	Audi	S4
2023	Audi	S4
2024	Audi	S4
2025	Audi	S4
2018	Audi	S5
2019	Audi	S5
2020	Audi	S5
2021	Audi	S5
2022	Audi	S5
2023	Audi	S5
2024	Audi	S5
2018	Audi	S5 Sportback
2019	Audi	S5 Sportback
2020	Audi	S5 Sportback
2021	Audi	S5 Sportback
2022	Audi	S5 Sportback
2023	Audi	S5 Sportback
2024	Audi	S5 Sportback
2025	Audi	S5 Sportback

Specifications:

Brackets	Precise
Brand	APR
Category	Exhaust
Clamping Type	Slip Clamp
1882	Yes
Emission Code	5
11205	Polished
1162	3.5
1163	Carbon Fiber with Brushed Inlay
1161	4
200	Brushed
9871	2.75
9871	2.50
9871	3.50
9882	Brushed
1174	Sound Absorption
1174	Helmholtz
Pipe Material	T304 Stainless Steel
Product Type	Exhausts (Catback Systems)
Sub Category	Exhaust and Tail Pipes
4369	2.5
Tube Connection	Butt Joint
6014	Yes
2126	OEM
Warning	California Proposition 65
Welding	TIG
Pipe Bend Type	Mandrel
Exhaust Tip Removable	Yes
Description_SHO	Exhaust
Description_INV	CATBACK, B9 S4 SEDAN
Description_DES	APR Catback Exhaust System - S4 / S5 (B9)
Description_EXT	Fits Audi S4 18-25, S5 18-25
Description_MKT	Introducing the APR Catback Exhaust System for the Audi B9 S4 and S5
Description_MKT	The APR Catback Exhaust System for the Audi B9 S4 and S5 is a complete, high-performance exhaust solution that runs the entire length of the vehicle from the catalyst back. Inspired by the larger center-pipe design of the higher-output RS4 and RS5 models, this system is engineered to boost performance, elevate sound, and enhance aesthetics with customizable exhaust tips that are sure to make a statement. Crafted from premium materials and built with advanced manufacturing techniques, this system is designed to withstand harsh conditions and deliver lasting performance. Expect a bold, aggressive growl at wide-open throttle, along with an impressive gain of 10 horsepower and 12 FT-LBS of torque to all four wheels!
Description_MKT	Unmatched Design and Precision Engineering
Description_MKT	Unlike anything currently available, the APR system includes downpipes extending to the factory catalyst in the upper engine bay, making this a true full-system upgrade. We’ve minimized restrictions with smooth transitions, oversized piping, and straight-through mufflers and resonators. Constructed from mandrel-bent T304 stainless steel with a brushed finish and TIG welding throughout, this exhaust system is as durable as it is striking. Installation is hassle-free, thanks to precision-fit brackets, OEM-style slip clamps, and an included upgraded tunnel brace to accommodate the oversized piping.
Description_MKT	Inspired by RS Performance
Description_MKT	Like the RS4 and RS5, this system features a reengineered exhaust routing design. It utilizes dual 2.5” (63.5mm) downpipes to dual 2.75” (70mm) midpipes pipes merging through a cast Y-junction into a massive 3.5” (91mm) midpipe, replacing the restrictive factory dual-pipe setup. The integrated Helmholtz resonator minimizes drone through a straight-through design with a sound-canceling port, ensuring no compromise in exhaust flow.
Description_MKT	The system splits again via another cast Y into two rear, valve-controlled mufflers with sound absorption technology. These valves are fully integrated with the OEM control system, adjusting automatically to enhance sound during aggressive driving while maintaining a quieter profile during cruising. Finally, exhaust gases exit through dual cast Y-junctions into a quad 2.5” (63.5mm) system, terminating in 3.5” (91mm) lightweight, single-walled motorsport-style tips. The tips feature a polished stainless steel finish and a subtle APR logo for a refined touch.
Description_MKT	Experience the APR Difference
Description_MKT	Designed for enthusiasts seeking the perfect balance of power, sound, style, and quality, the APR Catback Exhaust System for the Audi B9 S4 and S5 is a testament to engineering excellence. With its performance-driven design and durable construction, this system not only transforms your driving experience but also ensures years of reliable performance.
Description_FAB	Complete catalyst-back system including downpipes, extending from the factory catalyst back.
Description_FAB	Performance gains of 10 HP and 12 FT-LBS of torque delivered to all four wheels.
Description_FAB	Premium T304 stainless steel construction with TIG welding for strength and durability.
Description_FAB	Optimized flow through dual 2.5” downpipes, 2.75” midpipes, and a 3.5” midpipe.
Description_FAB	Mandrel-bent brushed piping paired with electropolished cast splitters for a refined finish.
Description_FAB	Precision brackets and slip clamps ensure accurate alignment and hassle-free installation.
Description_FAB	Includes an upgraded tunnel brace to accommodate the larger piping.
Description_FAB	Integrated Helmholtz resonator minimizes drone and enhances sound quality.
Description_FAB	Valve-controlled rear mufflers dynamically adjust sound based on driving style.
Description_FAB	Removable quad 3.5” motorsport-style polished tips with APR logo; optional styles available.
Description_FAB	Smooth transitions and straight-through components maximize performance by reducing restrictions.
Description_FAB	Strikes the perfect balance of power, sound, style, and quality for enthusiasts.
Description_FAB	Fully emissions compliant for worry-free operation.