Catback Valve Sonic Milltek Audi S4 B8.5, S5 8T - Valve Sonic Version - Resonated + Rear Muffler - Quad GT100 Black Tips

Milltek Sport Exhaust System for Audi S4 B8.5 / S5 8T

Is the original sound of your Audi S4 B8.5 / S5 8T leaving you wanting more? This Milltek Sport stainless steel exhaust system is the most requested upgrade among owners: more presence, a true sound signature, and build quality that lasts.

Technical specifications

• Milltek part number: SSXAU406
• Part type: Exhaust system
• Configuration: resonated (with intermediate muffler), with valves
• Detail: Valve Sonic version - With intermediate muffler + valved rear muffler - Quad GT100 black tips
• Tube diameter: 60.3 mm
• Outlets: 4 GT100 outlets of 100 mm
• Tip finish: black Cerakote (high-temperature ceramic)
• Fitting information: ValveSonic Electronic Valved System
• Material: aerospace-grade stainless steel
• Manufacturer: Milltek Sport (UK)

Fits the following vehicles

• Audi S4 B8.5 3.0 TFSi 333 hp (2012-2015)
• Audi S5 8T 3.0 TFSI B8.5 (Coupe - Cabriolet, 2011-2016)
• Audi S5 8T 3.0 TFSI B8.5 (Sportback, 2012-2016)

Not sure about fitment for your vehicle? Contact us with your VIN before ordering.

Most frequently asked questions

• Highway drone? It is the number one concern on forums. This version keeps an intermediate (resonated) muffler: the sound stays full under acceleration, but the system stays calm at steady speed, ideal for everyday driving.
• What about the neighbors in the morning? The valves are controlled as on the original: system closed and discreet on cold start or in comfort mode, fully open in sport mode.
• Fitting: the system uses the original mounting points. A repair shop with the right equipment typically fits it in one to two hours.

Why choose Milltek Sport?

Milltek Sport designs and manufactures its exhausts in England, with mandrel-bent tubes to preserve the internal diameter and a fit developed on the vehicle. The result: a clean installation without modification, and a sound tuned to stay pleasant for daily use.

Going further

• Cat-back exhaust, resonated or non-resonated: which one is right for your car?
• Valved exhaust system: how does it work and should you keep the valves?