Transform your BMW M5 F90 and BMW M8 F91 F92 F93 equipped with the 4.4 L S63 twin-turbocharged V8 with Redstar performance exhaust secondary cat delete. This lower secondary slip-on style downpipe only replaces the lower secondary pipes by removing the secondary catalytic converters for a cleaner, freer-flowing path. It is completely bolt-on and is designed not to trigger a check engine light.
Flow-optimised geometry improves exhaust evacuation for significant power gains, faster turbo spool and sharper throttle response, while adding a richer, more engaging exhaust tone. With OEM-style heat shielding option featuring a ceramic inner liner, radiant heat from the exhaust can be reduced by up to 80%, helping to control under-bonnet temperatures and supporting turbocharger longevity.
Engineered for precision fitment, Redstar utilises 2.0mm wall 304 stainless steel, 100% TIG welded and back purged construction, OEM-spec V-band flanges and factory-style brackets. Developed to interface seamlessly with OEM mounting points, this lower secondary solution delivers the durability, accuracy and integration expected from a Redstar performance exhaust downpipe upgrade for BMW M5 F90 and BMW M8 platforms.
Available Options
  - OEM-Style Heat Shielding: Redstar's signature thermal management system reduces radiant exhaust heat by up to 80%. Developed with motorsport-inspired materials and construction, it uses a multi-layer design of ceramic insulation and embossed stainless steel foil. Unlike wraps or coatings that degrade quickly, Redstar shielding delivers long-term durability and consistent protection for engine bay components.
Key Performance Benefits
  - Significant power gain
- Faster spool up and better throttle response
- Reduces under-bonnet temperature
- Adds a very nice tone to the exhaust
- 100% bolt-on installation
- Will not create a check engine light
Technical Specifications
  - Highest quality 2.0mm wall 304 stainless steel
- 100% TIG welded and back purged
- OEM-spec V-band flanges
- All brackets and mounts as on OEM unit
- Lower secondary slip-on style downpipe only - secondary cat delete