Brabus 800 Mercedes-AMG GT 63 4Matic+ (X290) Tuning Guide 2026 — Body Kit, Wheels & 800 HP

The Mercedes-AMG GT 63 4Matic+ (X290) four-door coupe is already one of the most aggressive super-saloons ever built in Affalterbach — 585 hp, 800 Nm, a 3.2-second 0-100 and a shape that looks angry sitting still. The Brabus 800 programme takes that platform and rewrites almost every meaningful number: 800 hp, 1000 Nm, a Widestar carbon body, 22-inch Monoblock forged wheels and a retrimmed cabin that turns the GT 63 into a coachbuilt grand tourer. This guide covers every element of the Brabus 800 conversion, the real competing programmes from Mansory and Larte Design, and what actually works on the X290 chassis.

Platform Overview

The X290 "4-Door Coupe" shares its architecture with the W213 E-Class and the C190 AMG GT, but the floorpan, subframes and rear suspension geometry are unique to the four-door car. It uses the M177 4.0-litre V8 biturbo with twin-scroll turbos mounted inside the cylinder banks (hot-V layout), a 9G-Tronic wet-clutch gearbox (AMG SPEEDSHIFT MCT 9G), fully variable 4Matic+ all-wheel drive with electronically controlled rear-axle torque vectoring, and rear-wheel steering on GT 63 and GT 63 S trims. Curb weight is around 2,045 kg, so the power-to-weight of a stock GT 63 is already 286 hp/tonne — the Brabus 800 lifts that to roughly 391 hp/tonne, Lamborghini territory.

Body Kits

Brabus 800 Widestar

The flagship programme. The Brabus Widestar widebody for the X290 is a full prepreg carbon-fibre conversion: wider front fenders (+25 mm per side), quarter-panel extensions (+30 mm per side), a new front bumper with integrated LED daytime running strip and active flaps behind the Panamericana grille, carbon canards, a vented bonnet insert with exposed-weave centre section, carbon side skirts with turbine-style inlets, a Brabus ducktail boot-lid spoiler and a multi-piece rear diffuser housing the quad stainless tailpipes of the Brabus valve-controlled exhaust. Every carbon part is gel-coated and UV-clear-lacquered in Bottrop; matte and gloss finishes are both offered. The kit is type-approved in Germany and comes with a TÜV-registerable data sheet, something most Chinese replicas cannot match.

Mansory Mercedes-AMG GT 63 S

Mansory offers a more extreme interpretation on the GT 63 S 4-Door. The Mansory programme replaces the entire front clip with a carbon unit featuring a massive trapezoid centre intake, dual-element LED bar, exposed carbon splitter and vented front fenders with cooling louvres. The rear gains a diffuser with fin-style strakes and a large carbon wing on risers. Mansory also offers an engine upgrade of its own — typically 830 hp — and bespoke "YN.5" forged wheels in 22" or 23". Styling is polarising: if the Brabus is coachbuilt restraint, Mansory is Geneva Motor Show theatre. Best suited to owners who want maximum presence rather than OEM-plus elegance.

Larte Design Wild Beast

Larte Design's Wild Beast kit, based in Moscow but engineered in Italy, is the budget-but-serious option. It consists of a front-bumper overlay (not a full replacement), bolt-on fender arches, carbon side-blade skirts, a rear diffuser insert and a choice of two rear spoilers: a subtle lip or a ducktail. The kit is offered in fibreglass-reinforced polymer as standard and in 100% carbon fibre at roughly double the price. Wild Beast does not widen the fenders as dramatically as Brabus or Mansory — it is an overlay programme — which keeps OE wheels usable and makes it easier to reverse should you decide to sell the car.

TopCar Inferno (limited)

TopCar Design — better known for its Porsche and G-Wagen work — has produced a small number of Inferno-style packages for the X290 on customer request. These combine a Brabus-style front bumper silhouette with TopCar's signature double-bar rear wing and Alcantara-lined interior inserts. Availability is build-to-order; lead time is typically 10-14 weeks.

Wheels

Stock GT 63 4Matic+ wheels are 20" or 21" staggered. The Brabus 800 programme comes with 22-inch Monoblock Z "Platinum Edition" forged wheels as standard: 9.5J x 22 ET38 front and 11.0J x 22 ET43 rear, wrapped in Michelin Pilot Sport 4S or 5S rubber — 265/35 ZR22 front and 305/30 ZR22 rear. Brabus also offers Monoblock P, S and Y designs at 21" for customers who prioritise ride quality over sidewall aesthetics. For Mansory conversions, YN.5 forged wheels in 22" or 23" are the signature choice (11J + 12J rear on 23s, which usually requires the Widebody fender flares). Aftermarket alternatives that suit the X290 include Vossen M-X series, HRE S1SC, ADV.1 ADV5.0 and Forgiato Tec 2.1 — all in forged two-piece or three-piece construction, which is important on a 2,045 kg car: cast wheels in 22" will flex and crack on European pothole roads. Tyre pressures should be monitored carefully on low-profile 35/30 profiles; Brabus recommends 2.6 bar cold front and 2.9 bar cold rear for road use.

Performance Upgrades

Stage 1 (625-650 hp): ECU remap only, using OBD-flash tools on MED17.7.5. Holds 25 km/h more in-gear and drops 0-100 to roughly 3.0 s. Completely reversible and safe on stock hardware provided 98-octane fuel is used.

Stage 2 / Brabus PowerXtra B40-700: Plug-and-play PowerXtra module with revised boost-control maps — 700 hp / 950 Nm. Uses stock turbos, stock intercoolers, stock exhaust. 0-100 in 3.0 s.

Stage 3 / Brabus 800: The full package. PowerXtra B40-800 control module, larger Brabus turbochargers with billet compressor wheels, high-flow intercoolers, stainless-steel downpipes with 200-cell sport catalysts, carbon air intake and a Brabus valve-controlled stainless exhaust with switchable butterflies. Output: 800 hp at 6,600 rpm and 1,000 Nm from 3,600 rpm (electronically capped from a natural 1,050+ Nm to protect the 9G-Tronic). 0-100 km/h in 2.9 s, 0-200 in 9.5 s. Brabus offers a 1-year / 100,000 km warranty on the entire conversion — something no independent tuner can match.

Exhaust-only options: Akrapovic Evolution titanium (-8 kg vs stock, +12 hp on a remap), Capristo valvetronic, iPE Innotech F1-Edition. All retain the factory catalytic converters unless the downpipe section is also replaced.

Interior

The Brabus 800 interior is a full leather and Alcantara retrim: Nappa leather on seat centres with contrast stitching, Alcantara on headliner and pillars, Brabus-branded illuminated aluminium scuff plates, carbon-fibre trim inserts replacing the factory piano black, Brabus floor mats with leather edging and B-logo embroidery on the headrests. An optional Brabus aluminium pedal set and sport steering wheel in Alcantara with a 12-o'clock stripe round out the package. Expect a 4-6 week cabin build time at Bottrop.

The Brabus 800 Technical Deep-Dive — Why It Is More Than a Remap

Many tuners claim 800 hp on the M177 engine. Very few deliver it reliably, and understanding why requires looking at the hardware. The Brabus 800 is not a software-only product — it is a complete air-path upgrade.

Turbochargers and intercoolers: The stock M177 turbos are sized for 585-630 hp. Push more boost through them and the compressor wheel spins past its efficiency island, producing hot, turbulent charge air that the stock water-to-air intercoolers cannot cool quickly enough — intake temperatures rise, the ECU pulls timing, and real-world power drops below the dyno number. Brabus installs larger-wheel turbos with billet compressors and pairs them with high-flow intercooler cores, because bigger turbos without bigger intercoolers simply do not work on this engine.

PowerXtra B40-800 and MED17.7.5: The B40-800 is a piggyback/tuning-box-plus-flash hybrid. It rewrites the MED17.7.5 ECU's torque-request and boost-pressure maps directly, then uses an additional harnessed module to correct MAP, MAF and rail-pressure signals in real time, so the ECU's protection strategies see nominal values even when the engine is making 1,000 Nm. This is why a B40-800 car does not throw MIL lights the way a crude tuning box does.

Downpipes and sport cats: Brabus fits 200-cell high-flow sport catalysts, not a full catless delete. Three reasons: (1) emissions compliance for EU6 and TÜV registration, (2) backpressure below ~180 mbar at redline to match the turbo housing, (3) catalyst thermal mass stabilises EGT — running catless on an M177 produces EGT spikes that shorten turbo life.

Torque limiter and warranty: The 9G-Tronic MCT gearbox is rated to roughly 1,000 Nm at the input shaft; Brabus raises the factory torque limiter from 800 to 1,000 Nm but does not exceed it, which is why the B40-800 is a 1,000 Nm programme rather than a 1,100 Nm one. The 1-year/100,000 km Brabus warranty covers the engine, turbos, intercoolers, downpipes and gearbox for the Brabus-registered VIN. The stock Mercedes warranty is typically voided on the drivetrain at the dealer's discretion, but because Brabus is a registered German manufacturer (Kleinserienhersteller), the Brabus warranty legally replaces it for the modified components.

Frequently Asked Questions

Does the Brabus 800 package void my Mercedes-Benz factory warranty?

In Germany and most EU markets, the Brabus conversion is treated as a factory-type modification because Brabus is registered as a small-series manufacturer. The Mercedes drivetrain warranty on modified components is replaced by Brabus's own 1-year/100,000 km warranty. Chassis, electronics and body warranty from Mercedes remain valid. Outside the EU the answer depends on your local dealer — we always recommend talking to them before ordering.

Can I fit the Brabus 800 Widestar body kit without the engine upgrade?

Yes. The body kit, wheels and interior are sold as standalone packages. Many customers start with the Widestar conversion and add the PowerXtra B40-800 a year or two later once the car is out of its factory powertrain warranty. The body kit alone takes roughly 3-4 weeks of workshop time and does not affect the drivetrain.

Will 22-inch Monoblock Z wheels ruin the ride quality on the X290?

The X290 runs AMG Ride Control+ adaptive air suspension. With correctly specified 265/35 front and 305/30 rear Michelin Pilot Sport 4S tyres on forged wheels, ride quality remains acceptable in Comfort mode — noticeably firmer than the factory 21s but a long way from harsh. Cast 22" wheels, by contrast, will transmit every imperfection because they lack the deflection absorption of a forged three-piece design.

How does the Brabus 800 compare with a Mansory 830-hp conversion?

Mansory and Brabus both start from the same M177 engine but take different approaches. Brabus prioritises OEM-level reliability, TÜV approval, a real 1-year/100,000 km warranty and slightly more restrained styling. Mansory pushes harder on peak output and aggressive visual drama but typically does not offer an equivalent factory-style warranty on the drivetrain. For a daily-driven grand tourer, Brabus is the safer choice; for a statement show car, Mansory is the more extreme one.