Active Autowerke F97 X3 M/F98 X4 M S58 AFlow Downpipes

Active Autowerke builds this pair of S58 downpipes for the BMW F97 X3 M and F98 X4 M. Each pipe carries a 4.5 in Active Autowerke AFlow high-flow catalytic converter, and Active Autowerke says no performance tune is needed to run them.

The factory S58 downpipes are restrictive, which slows exhaust flow out of the turbos and slows spool.

The Active Autowerke AFlow catted downpipe for the BMW X3M F97 and X4M F98 2020-2024 delivers a measurable improvement in exhaust flow and turbo response while remaining fully OBD2 compliant with no check engine light. The Active AFlow high flow catalyst uses advanced substrate technology to maximize flow while keeping emissions within OBD2 thresholds. Paired with 304 stainless steel mandrel-bent piping, this is a bolt-on upgrade that improves throttle response, reduces turbo lag, and adds a more aggressive exhaust note — all without triggering a CEL. OBD2 compliant — no check engine light (CEL)

What It Does

Turbochargers are driven by spent exhaust gas, and the quicker that gas leaves, the better the turbos respond. These downpipes open up flow right after the turbos for quicker spool and more power, with stainless flex joints and a step down to 70 mm to meet the factory exhaust. Active Autowerke never drops below the stock 70 mm diameter. Active Autowerke guarantees the AFlow cats against a cat-efficiency code, with full replacement within the first two years of ownership.

Materials and Construction

TIG-welded 304 stainless steel with cast stainless upper V-band clamps for a precise fit and a 400 cpsi catalyst substrate. They bolt on with no cutting or welding.

Features

• Pair of downpipes with 4.5 in AFlow high-flow cats
• 400 cpsi catalyst substrate
• Stainless flex joints, 70 mm outlet
• Cast stainless upper V-band
• No tune needed, per Active Autowerke
• Bolt-on, no cutting or welding

Specs

• Part number: 11-070A
• Brand: Active Autowerke
• Type: catted downpipes (pair)
• Catalyst: Active Autowerke AFlow, 4.5 in, 400 cpsi
• Outlet: 70 mm
• Engine: BMW S58 3.0L twin-turbo inline-six
• Shipping weight (Active Autowerke): 50 lb (22.7 kg)

Fitment Notes

• Active Autowerke fitment applies to US-model vehicles only.
• Active Autowerke covers the shell and tube ends for 5 years / 50,000 miles and the catalyst core for 2 years / 25,000 miles for the original buyer. Excessive burble (more than stock) voids the warranty because it destroys the catalyst core.
• Questions before you order? Call or text (310) 231-0292 or email Online@AutoTalent.com.
• Shop all Active Autowerke downpipes, every catted downpipe we carry, or the full Active Autowerke range.

FAQ

Do I need a tune?
Active Autowerke says no performance tune is needed.

GESI or AFlow?
GESI uses GESI cats; AFlow uses Active Autowerke's own cats at a lower price.

Is it bolt-on?
Yes, no cutting or welding is needed.