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
The BMW M3 CS (G80) (G80, 2021–present) runs the S58 and leaves the factory at 550 bhp · 650 Nm, M xDrive, 8-speed M Steptronic. Samuel tunes the G80 Saloon to the same standard — every map hand-calibrated for the specific car, its fuel grade and its installed hardware, not a base file loaded and left. M3 CS (G80) Stage 1 alone takes it from 550 bhp · 650 Nm to 650 bhp · 800 Nm on the standard turbo, flashed over OBD on BM3, MHD or MG Flasher.
Add the Stage 2 hardware and the M3 CS (G80) targets 720 bhp · 900 Nm; from there the S58 stretches to around 1500 bhp on a hybrid or big-turbo build with supporting fuelling. Whichever stage suits the M3 CS (G80), the file is delivered within 24 hours and is fully reversible to the supplied stock calibration.
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
M3 CS (G80) Stage 1 lifts the S58 from a stock 550 bhp · 650 Nm to 650 bhp · 800 Nm, with no hardware required. The map is flashed through the OBD port on BM3, MHD or MG Flasher and is the starting point for almost every M3 CS (G80) owner — broader torque and sharper throttle response from the factory hardware.
This page covers the G80 Saloon (G80). They share the S58 engine and run the same core calibration, but every M3 CS (G80) tune Samuel delivers is tailored to your exact car, fuel grade and installed hardware — never a base map loaded and left.
Stage 2 on the M3 CS (G80) targets 720 bhp · 900 Nm and needs downpipes + midpipe + intakes. Everything else — turbo, fuel system, intercooler — holds within the Stage 2 figures on the S58.
On the right hardware spec the S58 in the M3 CS (G80) reaches around 1500 bhp. Stage 1 and Stage 2 run the standard turbo; beyond that needs a hybrid or full big-turbo conversion with supporting fuelling, and the calibration is built bespoke per car.
Yes — later M3 CS (G80) (G80) cars ship with a locked DME that must be unlocked once before any map can be written. It's a one-time step; after that the M3 CS (G80) flashes normally over OBD and the tune is fully reversible to the supplied stock file.
Remotely. Once Samuel has your build details, the calibrated M3 CS (G80) map is delivered to your flashing tool account (BM3, MHD or MG Flasher) within 24 hours and you flash it yourself over OBD in about 15 minutes. It's fully reversible — the original S58 stock file is supplied before you flash, so the car can return to factory at any time.
A factory warranty can be voided if BMW shows a tune caused a specific failure, so it's a personal call. Samuel's M3 CS (G80) maps are calibrated to stay within the mechanical limits of the S58 hardware, and because the tune is reversible to stock before any dealer visit, many owners run a tuned M3 CS (G80) without issue.
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