Brabus Rocket 900 One of Ten - AMG GT 63 S (X290) Tuning Guide 2026

The Brabus Rocket 900 “One of Ten” is one of the rarest four-door super-saloons ever built. Limited to just 10 cars worldwide, it is based on the Mercedes-AMG GT 63 S 4Matic+ 4-Door Coupé (X290 chassis) and fitted with the full Brabus Rocket widebody, the hand-built 4.5-litre biturbo V8 and an individually numbered “1 of 10” plaque. With 900 hp and 1,250 Nm of torque, it sprints to 100 km/h in 2.8 seconds and reaches an electronically limited 330 km/h. This guide explains exactly what Brabus changes on the X290 Rocket programme, what you can still adapt on a standard GT 63 S, and how to spec the car to the same level.

Platform Overview

The GT 4-Door Coupé (X290) shares its platform with the E-Class (W213) but uses bespoke MRA-based subframes, wider tracks and the AMG Panamericana front end. Power comes from the M177 4.0-litre twin-turbo V8 in the GT 63 S, making 639 hp and 900 Nm in stock form. Brabus takes that engine completely apart: displacement is increased to 4,407 cc via a billet crankshaft with longer stroke, forged Mahle pistons, new H-beam rods and a precision-balanced rotating assembly. The factory turbochargers are replaced with new precision-balanced billet-wheel turbos, a larger intercooler, ported plenum and a bespoke stainless high-flow exhaust. The result is the 4.5L V8 biturbo — the same architecture as the Rocket 900 sedan and Rocket GTS programmes.

Body Kits

Brabus Rocket 900 Widestar — the full “One of Ten” package

This is the defining look of the car. The full carbon Rocket Widestar kit widens the X290 by 50 mm per side, lowers the visual centre of gravity and adds genuine aerodynamic function. At the front there is a new carbon bumper with integrated splitter, LED daytime running strip, twin canards per side and additional brake-cooling intakes. The vented carbon hood ducts hot air out of the engine bay on the motorway. At the rear you get fender flares with carbon outlet vents, a carbon ducktail spoiler, an aggressive diffuser with a central quad-exit exhaust and a re-profiled lower valance. Every piece is prepreg carbon, clear-coated and homologated by Brabus under the GT 63 S VIN. This is the only kit that makes the car a true “One of Ten”.

Mansory P900 4-Door

Mansory’s alternative for the X290 is visually louder and more theatrical than the Brabus. The P900 kit uses forged carbon with visible random-pattern weave on the front lip, hood, fenders, side skirts, rear diffuser and a fixed GT-style rear wing instead of Brabus’s ducktail. Mansory also offers its own matching interior programme (quilted leather with hexagon stitching, forged-carbon trim inlays) and its own 22” forged wheel designs. Performance-wise, Mansory typically pairs the P900 body with their own 900 hp M177 calibration, which is a conventional big-turbo + ECU approach rather than a stroked short-block. If your buyer wants presence above everything else, the P900 delivers; the Brabus is subtler and more technically ambitious.

Renntech R-Pack 850

RENNtech, the US specialist founded by ex-AMG engineer Hartmut Feyhl, takes a very different philosophy. Their R-Pack for the GT 63 S 4-Door focuses on calibration, cooling and chassis rather than wide carbon. You get an ECU/TCU flash to around 850 hp, a bigger intercooler, downpipes, a switchable exhaust, carbon-ceramic brake upgrades, spring/damper module and a discreet carbon lip, spoiler and diffuser set. It’s the option for owners who still want to use the car as a daily, pass for a factory car to casual observers, and spend most of the budget on how the car actually drives — not how it looks on Instagram.

Topcar Design Inferno Carbon

TopCar Design (Vladimir Popovich’s studio) offers a more understated but still wide kit with a strong Russian-market following. The Inferno GT programme for the X290 includes a carbon front lip, side skirt blades, fender flares, rear diffuser and ducktail, all in prepreg carbon with a choice of matte or gloss finish. It sits aesthetically between factory AMG and the full Brabus Rocket, and it’s a good choice if you are restoring or upgrading a used GT 63 S without going all-in on the “One of Ten” concept.

Larte Design Winner

Larte’s “Winner” kit is the most affordable real programme for the X290. It is a bolt-on FRP/carbon-composite set — front splitter, side skirts, rear diffuser, trunk spoiler and optional fender extensions — aimed at owners who want visual presence without the price tag of a full Widestar conversion. It works well with aftermarket 21–22” wheels and is the standard entry point for customers doing a staged build.

Wheels

The factory fitment on a Brabus Rocket 900 One of Ten is the Brabus Monoblock Z “Platinum Edition” forged wheel in 22”: 9.5J ET38 front and 11.0J ET50 rear, fitted with Michelin Pilot Sport 4S or Pilot Sport Cup 2 rubber (typically 265/30 ZR22 front, 305/25 ZR22 rear). The Z design is a 10-spoke forged monoblock with a machined centrelock-look cap and full carbon-fibre aerodisc option on the outer face to reduce drag at 300+ km/h.

Alternative forged sets used by Brabus and its customers on the X290 include the Brabus Monoblock Y (classic multi-spoke, also available up to 22”), Brabus Monoblock M (5-double-spoke, lighter), and ADV.1 / Vossen S17 / HRE P101 in the same 22” staggered spec. For track-oriented builds a 21” wheel on deeper sidewall (275/35 ZR21 and 315/30 ZR21) is a sensible downgrade — you lose a little presence but gain ride quality and protect the carbon-ceramic rotors from kerb damage. In all cases use a forged wheel: cast replicas cannot survive the mass and torque this car puts through its contact patch.

Performance

The Rocket 900 itself is the ultimate Stage for the M177 in the X290. Below that peak build, there is a clear staged ladder:

• Stage 1 — ECU flash only. Around 720–740 hp / 1,000 Nm from a pure software calibration (Brabus PowerXtra B40S-700, RENNtech R1, Weistec W.4). 0–100 drops to roughly 3.0 s. Reversible, invisible, pump 98 fuel.
• Stage 2 — downpipes, intercooler, intake. With 200-cell sport cats or catless downpipes plus a larger air-to-water intercooler and carbon intake, expect 780–820 hp. This is the point at which a higher-flow exhaust (Brabus stainless, Akrapovic Evolution, iPE F1) becomes audible and worthwhile.
• Stage 3 — billet-turbo upgrade. New billet-wheel turbos, port-matched manifolds, upgraded fuel pump and injectors take the short-block to around 850–880 hp. This is conceptually what Mansory and RENNtech 850 packages do.
• Stage 4 — full Rocket 900 short-block. Displacement increase to 4,407 cc, billet crank, forged pistons and rods, new precision-balanced billet turbos. 900 hp / 1,250 Nm electronically capped. This is the “One of Ten” specification.

Transmission reinforcement (clutch packs, valve body, TCU retune) is mandatory from Stage 3 onwards. The AMG 9G MCT is strong but not infinite. Cooling — aux radiators in the bumper, transmission cooler and a diff cooler — is what makes the difference between a car that makes 900 hp on a dyno and one that makes 900 hp lap after lap.

Interior

The factory “One of Ten” interior is finished in Brabus Fine Leather — typically Mastik black or Indianapolis Red — with red contrast stitching, Alcantara headliner, carbon door cards and an individually numbered build plaque on the centre console. Brabus also swaps the AMG steering wheel for a flat-bottom carbon/Alcantara item, upgrades the pedals to milled aluminium with rubber inserts, and fits illuminated “Rocket 900 1 of 10” door sill plates.

What Actually Changes

Stock GT 63 S — 639 hp, 900 Nm, 3.2 seconds to 100. Rocket 900 — 900 hp, 1,250 Nm, 2.8 seconds to 100. On paper the gap is a few tenths and a few hundred Nm. In the car, the whole character of the thing changes.

The first thing you notice is the sound. Stock, the M177 is a deep, cultured V8 that only lets its voice out in Sport+. The 4.5L biturbo with the Brabus stainless exhaust is harder and drier — there is less reverb, more edge, a clearer eight-cylinder firing order at idle and a serrated top-end note that the stock cats smother. In tunnels and underground garages it sounds genuinely angry.

Then the throttle response. Stock turbos need a breath to spool; the billet Brabus units pick up around 500 rpm earlier, so the car stops feeling like a turbocharged saloon and starts feeling like a big naturally-aspirated V8 that happens to have boost. Roll on from 2,500 rpm in any gear and the car doesn’t “build” — it just leaves. Mid-range pull from 3,000 to 5,500 rpm is the single biggest change: it’s the region where 1,250 Nm lives, and it pins four adults into their seats in a way the stock 900 Nm simply doesn’t.

Under braking the extra mass of the Widestar body is noticeable, but the carbon-ceramic brakes are unchanged and now feel slightly more eager because the pedal has to do less work relative to the chassis stiffness. At 250+ km/h the carbon hood vents, front canards and rear ducktail actually earn their place — the nose stays planted where a stock car starts to feel light. The ride on 22s and stiffer dampers is firmer around town but settles beautifully above 120 km/h. Passengers always comment on the sound, the acceleration and the stares from other drivers — roughly in that order, during the first week.

Frequently Asked Questions

Is the Brabus Rocket 900 One of Ten a new car or a conversion?

Technically it is a conversion: Brabus takes a factory Mercedes-AMG GT 63 S 4Matic+ 4-Door Coupé (X290), strips it, installs the 4.5-litre stroked V8, the Widestar carbon body, the Monoblock Z wheels and the bespoke interior, then re-registers the car with Brabus as the manufacturer in Germany (as a small-series manufacturer). Each of the ten cars has a unique Brabus VIN plaque in addition to its original Mercedes VIN. Legally, in most markets, it is titled as a Brabus Rocket 900.

Can I convert a used AMG GT 63 S into Rocket 900 spec later?

Partially yes, fully no. The visual Widestar kit, Monoblock Z wheels and interior package are available as separate Brabus components and can be retrofitted to any GT 63 S 4-Door by an authorised Brabus partner — we do exactly these builds at Hodoor. The stroked 4.5L short-block and the “1 of 10” build plaque, however, are reserved for the original ten cars. The maximum engine spec you can reach on a retrofit is the Brabus 900 package (without the numbered plaque) or a RENNtech/Weistec 850–900 hp build on the standard 4.0L block.

What tyres and pressures do you recommend for daily use on 22” Monoblock Z?

Michelin Pilot Sport 4S in 265/30 ZR22 front and 305/25 ZR22 rear is the best all-round choice — quiet, long-lived and rated for 300+ km/h. For dry-weather performance owners we use Pilot Sport Cup 2. Run 2.4 bar front / 2.6 bar rear cold for normal driving; drop 0.2 bar each end for track days. Avoid cheap run-flats: the Monoblock Z is designed for a conventional tyre construction, and run-flats spike NVH dramatically on the firmer Brabus dampers.

Does the 900 hp build hold up on European pump fuel?

Yes, with caveats. The Brabus calibration is mapped for RON 98 (Super Plus / V-Power 98) or higher. On RON 95 the ECU pulls timing and cuts boost — the car stays safe but effectively drops to around 780 hp. For the Middle East and North America, where 93 AKI / 98 RON is not always available, Brabus supplies a dedicated lower-octane calibration that caps the car at around 830 hp. Anti-lag, launch control and Drift Mode are retained on both maps.