Unleash 959 HP: CarBahn Stage 2 Performance Controller for the BMW G90 / G99 M5
The new BMW G90 / G99 M5 is already a powerhouse, but what if you could unlock supercar-level performance without sacrificing daily drivability? Enter the CarBahn Stage 2 Performance Controller, engineered by Steve Dinan and the CarBahn team. With 959 flywheel horsepower and 1,013 lb-ft of torque on 100-octane fuel, this plug-and-play controller is the most effective and reliable way to transform your M5.
Why Upgrade to Stage 2?
The factory M5 delivers 778 HP and 834 lb-ft impressive numbers, but the S68 engine has untapped potential. Stage 2 unleashes it. With dyno-proven gains of +181 HP and +179 lb-ft at the crank and +149 HP and +150 lb-ft at the wheels, you’ll experience instant acceleration and relentless pull across the rev range.
Unlike cheap piggybacks or risky ECU flashes, CarBahn’s controller is engineered to integrate seamlessly with BMW’s factory systems, keeping your car’s safety features intact.
Plug-and-Play Simplicity
CarBahn designed the Stage 2 Controller for ease of use and peace of mind:
Quick Install – Installs in under one hour, no ECU unlock required.
App Control – Switch maps instantly for 91, 93, or 100-octane fuel.
Reversible – Restore your BMW to stock at any time without leaving a trace.
VIN-Locked – Security built in to prevent unauthorized use.
This isn’t a one-size-fits-all module. Each map is calibrated with precision, tested extensively on the dyno and on track, and tailored specifically for the G90/G99 M5 platform.
Power with Peace of Mind
Performance means nothing without reliability. That’s why CarBahn tunes are engineered with safety first:
Factory Safeguards Intact – No disabled safety protocols.
Thermal Management – Prevents overheating during aggressive driving.
Supporting Hardware Required – For Stage 2, the CarBahn Heat Exchanger (CBB08-90-2052) is required to manage intake temps and qualify for warranty coverage.
OEM-Level Engineering – Backed by Steve Dinan’s legacy of building reliable, track-tested upgrades.
When paired with the proper supporting mods, Stage 2 provides extreme performance that you can enjoy every day without compromise.
How It Works
The Stage 2 Controller uses advanced calibration strategies to safely extract more power from the S68 engine. Through Bluetooth, the controller communicates with your phone, giving you full control of octane maps from the CarBahn app (available for iOS and Android).
Switching between 91, 93, or 100-octane maps is seamless, making it easy to adapt to different driving environments or fuel availability.
Proven on the Dyno
CarBahn doesn’t deal in guesses we back every claim with data. On 100-octane fuel, Stage 2 pushed the G90 M5 to:
959 HP / 1,013 lb-ft (flywheel)
On 93-octane fuel:
909 HP / 963 lb-ft (flywheel)
131 HP / +129 lb-ft gains vs stock
These results are the product of thousands of hours of dyno tuning, road testing, and track validation.
Fitment and Compatibility
Model: BMW M5 (G90 Sedan, G99 Touring)
Years: 2025–2026
Engine: S68 twin-turbo V8
Transmission: Automatic, xDrive
Stage: Stage 2 (requires CarBahn Heat Exchanger)
View the Stage 2 Performance Controller →
Frequently Asked Questions
Does the Stage 2 Controller require ECU flashing?
No. It’s a plug-and-play module that leaves the ECU untouched, preserving factory safeguards.
Will this void my factory warranty?
Any aftermarket modifications can affect your warranty, however our products are tested with vehicle safety in mind and come with the option of replacing your powertrain warranty for peace of mind.
What happens if I run 93-octane instead of 100-octane?
The controller will deliver safe, dyno-proven gains on 93-octane (+131 HP / +129 lb-ft). For maximum performance, 100-octane is recommended.
Can I return my M5 to stock?
Yes. The Stage 2 Controller is fully reversible, allowing you to return to factory power levels at any time.
Why Choose CarBahn?
CarBahn is built on Steve Dinan’s engineering legacy decades of tuning, racing, and developing performance upgrades for BMWs. Unlike generic modules, CarBahn products are:
OEM+ – Enhancements that feel factory, not aftermarket.
Track-Proven – Lessons from motorsport applied to street cars.
Reliability-Focused – Safety protocols and long-term durability prioritized.
When you choose CarBahn, you’re not just buying horsepower you’re buying peace of mind.