Milltek Sport Audi RS3 Sportback 8V Large-Bore Downpipe and Hi-Flow Sports Cat

Milltek Sport's Large-Bore Downpipe and Hi-Flow Sports Cat for the Audi RS3 Sportback 400PS combines two upgrades in one package, a genuinely larger-diameter downpipe paired with a higher-flow metal substrate cat, replacing the factory catalytic converter with something that flows considerably better while still retaining meaningful emissions control. This is a sensible middle-ground option for owners wanting a substantial flow improvement without going the full de-cat route.

Constructed from T-304 stainless steel throughout, this system is built to outlast the factory components it replaces, resisting the corrosion that eventually catches up with mild steel factory parts. Reducing backpressure across both the downpipe and catalytic converter sections at once delivers a more complete performance upgrade than addressing either section individually, particularly noticeable when paired with a supporting ECU tune.

Why Choose This Downpipe and Hi-Flow Sports Cat

• Combines a larger-bore downpipe with a higher-flow sports cat in one package
• Retains meaningful catalytic converter function, unlike a full de-cat pipe
• T-304 stainless steel construction throughout, built for long-term durability
• Particularly effective when paired with a supporting ECU tune

Compatibility

• Audi RS3 Sportback 8V