Remus Racing Exhaust System for BMW M5 F90 Limo Decat Pipe | 4x 100mm Titanium Black Tips 1-089317-1000-7

At an engineering level, this is a high-flow, motorsport-oriented exhaust package for the F90 M5’s 4.4-liter twin-turbo S63 V8. 

REMUS describes the Racing system as using lightweight construction, high-grade materials, integrated exhaust valves and a non-resonated front section. 

🔥 What makes the system special

1. Non-resonated front section

The REMUS 089317 0000 replaces the front cat-back section and increases tubing from approximately 80 mm OEM → 84 mm REMUS. 

Removing the resonated section reduces restriction and gives the V8 a much more aggressive exhaust character. 

Think of it as:

S63 V8 → turbochargers → freer-flowing exhaust path → valves → four large tips

The reduced back-pressure is particularly interesting once the engine is producing substantially more power than stock.

2. Valve-controlled exhaust

The Racing axle-back uses integrated valves operated through the BMW’s original valve actuators/electronics. That means the system can retain the fundamental concept of factory valve control rather than simply being permanently loud. 

3. Titanium-black visual signature

The four large black titanium-style tips give the M5 a much more motorsport-oriented appearance. REMUS offers several tailpipe configurations, including titanium and black-finished options; the exact tip specification should therefore be checked against the seller’s 1-089317-1000-7 configuration because REMUS lists several interchangeable tailpipe packages. 

🧠 Engineering interpretation

The important part isn’t simply “bigger exhaust = more horsepower.”

The S63 is already a highly boosted V8. Exhaust design influences:

• Back-pressure
• Turbocharger pressure ratio
• Exhaust-gas energy
• Turbo response
• High-rpm flow
• Acoustic character
• Thermal management

A freer-flowing system can give the turbochargers an easier route to evacuate exhaust gas. The benefit becomes more meaningful as airflow increases with tuning.

REMUS itself claims performance and torque increases and lower back-pressure for its Racing system. 

📊 F90 M5 character

Area	OEM exhaust	REMUS Racing
Sound	Refined	Aggressive
Exhaust flow	OEM-oriented	Higher-flow
Valve operation	Factory	Retained
Turbo breathing	Conservative	Less restrictive
High-RPM character	Smooth	More intense
Weight	Higher	Weight-optimized
Appearance	OEM	Motorsport
Road legality	Depends on configuration	Racing components may not be road approved

REMUS explicitly states that its Racing components without EC approval are not intended for public-road use. 

⚠️ Important F90 compatibility point

There is a major distinction between pre-GPF/OPF and GPF/OPF-equipped F90s. REMUS lists the Racing system for specific F90 configurations, and its documentation notes different applications depending on whether the car has GPF/OPF. 

So the production year and emissions configuration of the M5 must be matched to the exact REMUS part number before purchase.

🏁 The final philosophy

The REMUS Racing system transforms the F90 M5 from a luxury super-sedan with a V8 into something acoustically and mechanically closer to a GT-style performance machine:

4.4L Twin-Turbo V8
↓
Lower exhaust restriction
↓
Better high-flow capability
↓
Sharper turbo/exhaust response
↓
Valve-controlled aggression
↓
Four large titanium/black outlets
↓

S63 V8 — executive sedan outside, race-bred soundtrack underneath.

For a closed-course/track-oriented build, this is considerably more interesting than simply changing the rear mufflers because the non-resonated front section changes the flow characteristics of the entire cat-back system. 

REMUS also recommends ECU calibration for closed-course applications when using its racing exhaust components to optimize performance and avoid warning-light issues. 

Remus Racing Exhaust System for BMW M5 F90 Limo Decat Pipe | 4x 100mm Titanium Black Tips 1-089317-1000-7