Active Autowerke Downpipes with Aflow Cats – G87 M2 | G80 M3 | G82 M4 (S58)

No tune needed. No CEL. Built for power.

The Active Autowerke Aflow Downpipes replace the restrictive factory units on your S58-powered BMW, freeing up horsepower, sharpening throttle response, and adding a deeper, more aggressive exhaust tone — all while staying emissions compliant in 49 states.

Made from 304 stainless steel, these 3” TIG-welded downpipes feature 4.5” high-flow Aflow catalytic converters rated for up to 800 HP. The design minimizes back pressure, improves turbo spool, and bolts directly to your OEM exhaust with no cutting or welding required.

Key Features

• No tune required
  
• No CEL for cat efficiency
  
• 3” mandrel-bent 304 stainless steel piping
  
• 4.5” Active Aflow high-flow cats (EPA registered, 49-state legal)
  
• Quicker turbo spool and more midrange torque
  
• Handles temps up to 1500°F
  
• Direct bolt-on fitment with OEM-style flanges
  
• Made in Miami, Florida

Warranty

• 5-Year / 50,000-Mile on shell & tubing
  
• 2-Year / 25,000-Mile on catalytic core
• Warranty void if excessive burble tuning damages cats

Notes

• Not legal for use in California
  
• For off-road or race use only where applicable