Valvetronics

Valvetronic Designs G8X M2/M3/M4 400 Cell Catted Downpipes

SKU: BMW.G8X.M2.M3.M4.FF.400C.BR
$3,399.95 AUD

BMW G8X M2 / M3 / M4 – EPA-Compliant 400 Cell Catted Downpipes
Engineered for the S58 Twin-Turbo Inline-6 • High-Flow • Emissions Compliant

The BMW G8X M2, M3, and M4 mark the latest evolution of M performance, built around the formidable S58 twin-turbo inline-6. Factory catalysts are designed around restriction and sound suppression — Valvetronic Designs' 400 cell EPA-compliant high-flow catted downpipes are engineered to cut exhaust backpressure, sharpen turbo efficiency, and unleash a more aggressive exhaust character, all while staying within emissions compliance standards.

This upgrade unlocks more of what the S58 platform is capable of, without sacrificing everyday drivability.

Why Upgrade to 400 Cell?

  • EPA-Compliant 400 Cell High-Flow Catalysts — increased exhaust flow while maintaining compliance standards
  • Improved Turbo Response — reduced restriction enhances spool speed and mid-range power delivery
  • Enhanced Exhaust Character — deeper tone with more defined turbo acoustics and sharper high-RPM presence
  • Street & Track Ready — noticeable gains while maintaining everyday usability

Performance & Engineering

  • Optimised flow architecture that minimises backpressure while preserving catalyst efficiency
  • Mandrel-bent tubing for smooth internal transitions and consistent exhaust velocity
  • Precision TIG welding built to withstand extreme exhaust temperatures and high boost levels
  • Direct OEM bolt-on installation using factory mounting locations
  • Engineered to pair seamlessly with Valvetronic exhaust systems

Sound Transformation

  • Stock Exhaust + Downpipes: noticeable increase in depth and turbo presence with improved exhaust clarity
  • Valvetronic Exhaust + Downpipes: maximum transformation — stronger crackles, enhanced turbo spool acoustics, and a more aggressive overall signature

Construction & Durability

  • Premium high-grade stainless steel construction
  • High-temperature resistant 400 cell catalyst cores
  • OEM-style sensor placement for proper operation
  • Engineered for long-term reliability under high boost and tuning conditions

Unleash the full potential of your S58-powered G8X — starting at the source.

Fitment: BMW G87 M2, G80 M3, G82/G83 M4 (S58 engine)

Special Order Item

This product is imported from overseas specifically for your order.

The listed price includes shipping to Australia unless otherwise stated.

Please note: Import duties, GST, customs clearance fees and any other charges assessed upon arrival in Australia are not included and remain the responsibility of the purchaser.

Important Information:

This product is intended for performance use and should be installed by a qualified professional.

It is the customer’s responsibility to ensure compatibility with their specific vehicle prior to purchase. If you are unsure, please contact us before ordering.

Gridline Custom Motorsports is not responsible for issues arising from incorrect installation, misuse, or improper product selection.

Due to the nature of performance parts, some items may be special order and subject to supplier availability and lead times.