Tuning · BMW M3 CS (G80) (G80)
M3 CS (G80)
S58
The CS treatment for the G80 M3, sharper factory map, stiffer chassis setup, all-wheel-drive only. Hand-calibrated from Stage 1 to a fully bespoke big-turbo build. Same S58 hardware as the standard G80 M3, with a 550 bhp / 650 Nm factory starting point instead of 503 / 650.
Engine
S58
Stock
550 bhp · 650 Nm
Stage 3 ceiling
550 bhp
About this tune
The G80 M3 CS (2023-present) is the lightweight, more aggressive derivative of the G80 M3 Competition, same S58 twin-scroll twin-turbo straight-six, with a sharper factory map (550 bhp / 650 Nm vs 503 / 650 on the standard Competition). xDrive only, M-DCT only. The CS treatment includes lighter wheels, a stiffer chassis setup and an aggressive factory throttle calibration, and it tunes identically to every other S58 car from a hardware ceiling standpoint.
BMW M3 CS (G80) tuning
Only a limited number of G80 M3 CS cars were built, and each one arrived with the sharpest factory S58 map BMW sells, 550 bhp against the standard Competition's 503, with xDrive and the 8-speed M Steptronic as the only configuration. CS owners come to Samuel because the extra money bought lighter wheels and a harder chassis, not extra ceiling: under the bonnet the hardware is identical, and the same headroom is waiting.
Stage 1 moves the M3 CS from 550 bhp and 650 Nm to 650 bhp and 800 Nm, a smaller step than a standard G80 takes because BMW already spent part of the margin. Stage 2, on downpipes, a midpipe and intakes, reaches 720 bhp and 900 Nm, and the Flex Fuel option stretches E50 blends towards 800 bhp. The calibration is built for your individual car, not adapted from a base M3 file.
As with every G80, the CS's DME is locked when it leaves the factory; Samuel handles the one-time unlock and it never needs doing again. From there the route to around 1500 bhp runs through hybrid and full-frame turbo hardware with port injection and flex fuel. Files are written remotely to BM3, MHD or MG Flasher within a day, and the untouched stock CS map stays with you for whenever you want it back.
Configurator
Build your M3 CS (G80) tune
Choose your stage — Stage 1, Stage 2 or Stage 3 — add the options that fit your car, and send the full build to Samuel for a custom remote remap. He'll quote, schedule, and personally calibrate within 24 hours of confirmation.
Add a stage or add-on
£0
Engine guide
BMW M3 CS (G80) tuning, stages, hardware and what to expect from the S58
The G80 M3 CS runs the S58, same twin-scroll twin-turbo straight-six as the standard G80 M3 Competition, with a sharper factory map. BMW set the M3 CS at 550 bhp / 650 Nm versus 503 / 650 on the standard Competition. The engine block, head, turbos, fuelling and DME are identical between the two cars; only the software limiter and a stiffer chassis setup separate them. BMW M3 CS G80 tuning with Samuel uses the same map ethos as the standard G80 M3, the CS just starts from a higher baseline, so the Stage 1 / Stage 2 ceilings sit at the same final figure.
Stage 1
650 bhp · 800 Nm
No hardware required. The MG1 DME is flashed via the OBD port, boost pressure, ignition timing, fuel delivery and torque limiters all revised. BMW M3 CS Stage 1 unlocks 650 bhp / 800 Nm from the OEM hardware (up from 550 / 650 stock), with a substantially broader torque curve through the mid-range. Same Stage 1 ceiling as the standard G80 M3, the hardware is identical.
Every M3 CS tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW M3 CS G80 tuning done correctly accounts for the CS chassis stiffness, the M-DCT calibration and UK fuel quality; the map is reviewed against your data logs after the first flash and revised before sign-off.
Compatibility
Platform and hardware compatibility
Bootmod3 (BM3)
Full S58 support including the M3 CS. MG1 DME OBD flashing, realtime monitoring, and licence management via the BM3 app. The most widely used platform for G80 M3 CS tuning.
Read more →
MHD
Full S58 support. Suitable for Stage 1 and Stage 2 on the M3 CS. Strong data-logging toolset.
Read more →
MG Flasher
Full S58 support. Clean interface and reliable flash process on the MG1 DME.
Read more →
xHP Flashtool
Compatible with the 8-speed M-DCT on the G80 M3 CS. Strongly recommended at Stage 2, available as an add-on. The CS chassis is xDrive-only, so the gearbox calibration is matched to the AWD logic.
Read more →
ECU: MG1 DME. Accessible via OBD port, no bench flash required for Stage 1, Stage 2 or Stage 2 Flex Fuel.
M3 CS (G80) specs & stage targets
BMW M3 CS (G80) tuning at a glance
- Engine
- S58
- Body styles
- G80 Saloon
- Chassis codes
- G80
- Production
- 2021–present
- Drivetrain
- M xDrive
- Gearbox
- 8-speed M Steptronic
- Stock output
- 550 bhp · 650 Nm
- Tuning ceiling
- ~1500 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 650 bhp · 800 Nm |
| Stage 2 | 720 bhp · 900 Nm |
| Stage 3, Hybrid Turbo | 800-1500 bhp depending on spec |
| Stage 3, Big Turbo Kit | 800-1500 bhp depending on spec |
FAQ
M3 CS (G80) tuning — frequently asked questions
From a hardware standpoint, no. The CS runs the same S58, turbos and fuel system, so its Stage 1 and Stage 2 ceilings match the standard car. What differs is the starting map: BMW ships the CS with a more aggressive factory calibration, so Samuel builds on that character rather than overwriting it with a generic G80 file.
The headline step to 650 bhp is smaller, yes, around 100 bhp instead of nearly 150, but the finishing point is the same and the torque increase to 800 Nm is identical. In practice the CS's lighter weight and stiffer setup make the tuned output feel more immediate than the raw numbers suggest.
No more than any other G80-generation car. The DME is unlocked once, a standard step Samuel walks you through, and afterwards the CS reads and writes maps over OBD exactly as an older M3 would. The unlock does not alter the factory calibration itself; your original CS map is preserved and supplied back to you.
The S58 platform runs to roughly 1500 bhp at the extreme. Past the 720 bhp Stage 2 point the route is a hybrid turbo, then a full-frame turbo kit with port injection and a flex-fuel setup. Each of those is a bespoke calibration priced against your exact parts list, so send Samuel the full build spec first.
That is arguably what the CS is for. Samuel calibrates with sustained load in mind, controlled boost targets, sensible exhaust gas temperatures and a torque curve that stays predictable on corner exit rather than spiking. Pair the map with proper cooling maintenance and fresh fluids and the car remains a track tool, just a significantly faster one.
Keep exploring
Keep exploring M3 CS (G80) tuning
Other S58 models we tune: M2, M3, M4, M4 CS (G82), X3 M, X4 M.
Engine guide
S58 tuning
Every S58 BMW we calibrate, with the full Stage 1, 2 and 3 breakdown for the engine.
Learn moreStages
Stage 1 & Stage 2 explained
What separates Stage 1 from Stage 2 on the M3 CS (G80), the real-world gains and the hardware each one needs.
Learn morePricing
How tuning is priced
How the licence, off-the-shelf maps and custom calibration are priced. We quote your exact spec, never a fixed menu.
Learn moreGuide
What is bootmod3?
New to remote flashing? A plain-English explainer on the platform and how a custom map reaches your car.
Learn moreBefore you flash
ECU unlock guide
Newer M3 CS (G80) ECUs ship locked from the factory and need unlocking before any tune. Here is how it works.
Learn more