Who knew that the Mercedes-AMG GT 63 S is a supercar hiding in plain sight?

The Mercedes-AMG GT 63 S is arguably the most fancied Mercedes in the market today. It combines the best of Mercedes and AMG into one package, and, as we’ve come to know lately, there’s also enough space for an aftermarket tuner to slip in and add its own spin to the luxury performance saloon. Take this particular AMG GT 63 S, for example. On its own, it already packs a whopping 630 horsepower and 664 pound-feet of torque coming out of a 4.0-liter twin-turbocharged V-8 engine. That’s enough output to help the four-door saloon sprint from 0 to 62 mph in 3.2 seconds on its way to a top speed of 196 mph. These are fantastic numbers on their own, but when you add a known Mercedes performance tuner like Performmaster into the mix, you end up getting the equivalent of automotive madness.

If you know your Mercedes tuners, you know that Performmaster has made good business out of creating tuning programs for Silver Arrow models. The tuner’s area of expertise revolves around software upgrades, and we’ve seen a handful of them over the years, including one for the 2015 Mercedes E 63 AMG, among many others. If it’s not building its own programs, Performmaster has also collaborated with a number of other tuners, supplying them with software engine upgrades for their own aftermarket programs.

This project for the Mercedes-AMG GT 63 S, however, is all Performmaster. It’s unique in its own way because it’s actually a special edition build that celebrates the tuner’s 31st anniversary in the aftermarket biz. It has all the signs of a proper special edition program, including a limited quantity of just 31 builds. It’s basically a special edition aftermarket program, which is like killing two birds with one stone.

Mercedes-AMG GT 63 S - standard vs tuned
Mercedes-AMG GT 63 S Specs Mercedes-AMG GT 63 S by Performmaster Specs
Engine 4.0-liter twin-turbocharged V-8 engine 4.0-liter twin-turbocharged V-8 engine
Horsepower 640 horsepower 740 horsepower
Torque 664 pound-feet of torque 760 pound-feet of torque
Transmission nine-speed automatic transmission nine-speed automatic transmission
Drive Four-wheel-drive Four-wheel-drive
0 to 62 mph 3.2 seconds 2.9 seconds
Top speed 196 mph Over 200 mph (estimate)
Ever Wondered How Fast the Mercedes-AMG GT 63 S Could Be When Properly Tuned?
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Before we dive deep into the significant engine upgrades of this program, it’s important to note that the Mercedes-AMG GT 63 S also comes with aftermarket aero pieces from Aersphere. A number of pieces, in particular, are worth talking about. Up front, there’s the front sword and saber — that’s how Performmaster calls what looks like the splitter — that smoothens this section of the car’s whole surface area. There’s also the rear wing, which enhances the aero qualities on the AMG GT 63 S’ rear axle.

That manifests itself in improvements in the four-door saloon’s handling and driving stability on the straight and in the corners, particularly at high speeds.

The other significant piece of equipment is the rear diffuser, which should help keep the AMG GT 63 S stuck to the ground even as it’s rampaging along on a race track.

The AMG GT S 63 is perfectly suited to do just that even with an unbesmirched 4.0-liter twin-turbo V-8 engine. After all, that V-8 unit can produce 630 horsepower and 664 pound-feet of torque, enough to propel it to go from 0 to 62 mph in 3.2 seconds on its way to a top speed of 196 mph. That’s all great and dandy, but we all know that there’s more power inside that V-8 engine, waiting to be tapped. This is where Performmaster comes in.

Ever Wondered How Fast the Mercedes-AMG GT 63 S Could Be When Properly Tuned?
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As you might expect, Performmaster’s engine upgrade program for the AMG GT 63 S doesn’t include any new hardware. There are no bigger turbochargers waiting to be dropped, no new cylinder heads, and, certainly, no new gaskets or intercoolers. There’s only the tuner’s PEC tuning module, which is really more than enough to access the requisite increase in output that justifies the AMG GT 63 S’ billing as a four-door powerhouse. Performmaster gets its desired output for the four-door Merc-AMG by simply connecting the tuning module to the AMG engine control unit.

A few software nips here and a few software tucks there and presto ala presto, the AMG twin-turbocharged V-8 engine now produces a knee-buckling 740 horsepower and 760 pound-feet of torque.

Do the math, and that adds up to an output increase of 110 horsepower and 96 pound-feet of torque compared to what suddenly looks like a rather mundane 640-horsepower Mercedes-AMG GT 63 S. Note the figures, folks. With that much output under its hood, the Performmaster-tuned Mercedes-AMG GT 63 S is effectively a four-door supercar that can run roughshod over the Porsche Panamera Turbo S, Aston Martin Rapide AMR, and BMW M760i xDrive.

Ever Wondered How Fast the Mercedes-AMG GT 63 S Could Be When Properly Tuned?
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Consider this: the limited edition Performmaster-tuned Mercedes-AMG GT 63 S can now accelerate from 0 to 62 mph in 2.9 seconds. Not only is that 0.3 seconds faster than the standard AMG GT 63 S, but it’s almost as fast to 62 mph as the vaunted Lamborghini Aventador SV, which clocks in at only 2.8 seconds. Aftermarket upgrades notwithstanding, when was the last time a Mercedes-AMG model was mentioned in the same breath as a Lamborghini Aventador SV? Probably never, right? Sport Auto conducted its own test of the car’s performance abilities, and it clocked a 0-t0-62-mph time of 3.0 seconds, just 0.1 seconds off Performmaster’s claims.

The tuner also performed tweaks to the AMG GT 63 S’ suspension, bringing the whole limited edition program full circle.
Ever Wondered How Fast the Mercedes-AMG GT 63 S Could Be When Properly Tuned?
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I’ll say this much about Performmaster. In the years that I’ve seen the tuner’s handiwork, I’ve never thought of the German tuner in the same vein as Mansory and Brabus. Whereas those tuners often go to great lengths — sometimes, to extremes — to showcase their tuning chops, Performmaster goes about its business without so much as a fuss. We rarely hear about its projects, and in the times that we do, it’s almost always in collaboration with another tuner.

But this Mercedes-AMG GT 63 S is proudly Performmaster’s work. It’s a celebration of the company’s 31st anniversary and the limited nature of the build — only 31 units will be created — hammers that point home. There’s no announced price tag for the whole build, but you can definitely expect it to cost more than the €167,016 — that’s about $195,000 based on current exchange rates — price tag of the standard AMG GT 63 S.

Ever Wondered How Fast the Mercedes-AMG GT 63 S Could Be When Properly Tuned?
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So, go ahead and puff your chest, Performmaster for 31 years of being one of the finest Mercedes tuners in the world. You’ve certainly earned the flex.

Further reading

2019 Mercedes-AMG GT 4-Door Coupe Exterior
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but it’s pretty damn cool anyway

Read our full review on the 2019 Mercedes-AMG GT Four Door

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