G-Power->ke1323 is often considered one of the best BMW->ke178 tuners in the game. But every so often, it takes a detour and works on models from Bavaria’s biggest rival, Mercedes-Benz.->ke187 Back in September 2015, the tuner presented a program for the 2015 S63 AMG that put 695 horsepower and 737 pound-feet of torque into the sedan’s 5.5-liter bi-turbo V-8 engine. That’s notable because it only took a few months for G-Power to go back to the S-Class->ke359 catalog and build another program for Mercedes’ flagship family.

This time, the focus was put on the AMG S63 Coupe, a car that’s slowly ingratiating itself into the conversation as one of the most popular high-performance variants of the AMG->ke8 lineup. It’s also become a favorite among tuners so it’s easy to see why G-Power decided to work on its own program for the model.

For this kit, the German tuner opted for something more straight-forward than its usual tuning strategy. The exterior and interior of the car were left mostly alone so all the focus was placed on giving the car’s 5.5-liter biturbo V-8 an upgrade that’s fit for a king. The tuner accomplished that and then some with this program, which goes to show that when it comes to aftermarket skills, G-Power doesn’t discriminate between BMW or Mercedes-Benz models.

All’s fair in love and the tuning game, so to speak.

Continue after the jump to read the full review.

Exterior

Exterior modifications are kept at a minimum with the only notable upgrades being the new set of 21-inch Hurricane RR wheels that have replaced the standard set. These wheels are made from 6061-grade aluminum, the same material that’s commonly used in the aerospace industry for its combination of lightweight and high-strength qualities. The wheels are also wrapped in 265/30- and 295/30-series tires in the front and rear, respectively.

That may not sound like something that’s worth the attention, but the fact that it’s lighter than the standard set of wheels means that it helps reduce unsprung mass while also helping improve the AMG63 S Coupe’s performance capabilities.

Interior

This program is all about the AMG 63 S Coupe’s 5.5-liter twin-turbo V-8 engine so don’t expect any upgrades on the interior. It’s a little disappointing not having any added bits to the cabin but not to the point that the kit itself loses any appeal. Besides, when it’s got an engine upgrade as impressive as the one G-Power prepared for it, customers who do end up getting the kit likely won’t mind that the interior was left untouched.

Drivetrain

Now to the highlight of the program. In order to achieve the necessary performance improvement on the AMG 63 S Coupe, G-Power installed its own Bi-Tronik 5 V1 power upgrade, helping the high-performance coupe’s 5.5-liter twin-turbo V8 engine achieve an output of 705 horsepower and an incredible 738 pound-feet of torque. Those numbers represent a significant increase from the V-8’s standard output of 585 horsepower and 664 pound-feet of torque.

The coupe’s new performance numbers reflect the dramatic increase in power. For instance, the sprint to 60 mph has been reduced to 3.8 seconds – one-tenth of a second quicker than the standard model. Likewise, top speed is now rated at 205 mph after removing the Vmax limiter. That’s a dramatic improvement from the coupe’s electronically limited 155-mph top speed.

The plug-and-play nature of G-Power’s Bi-Tronik 5 V1 module means that the kit can be easily removed to restore the original setting of the engine. I don’t know who would do that, but it is understandable for somebody who may prefer to go back to the car’s original capabilities after having one too many run-ins with the law. Engine protection and diagnosis functions are also intact, giving customers the option of using the module when needed.

Pricing

The Bi-Tronik 5 V1 engine module costs €5,589, which is about $6,155 based on current exchange rates. Those who avail of the 21-inch Hurricane RR wheels and tires will have to shell out an extra €7,373. That’s around $8,120 based on current exchange rates, bringing the total amount to about $14,275.

Competition

Mercedes-AMG S63 Coupe Black Edition By Mansory

G-Power is mostly known for its programs on BMW models so it is a bit surprising to see the German tuner work on a Mercedes. It’s also worth noting that another tuner recently unveiled its own kit for the AMG S63 Coupe. That tuner was Mansory and it’s own program featured, among other things, a carbon fiber body kit that includes spoilers, wider fenders, hood vents, extended side skirts, and a fixed rear wing. The interior, meanwhile features leather upholstery and carbon inserts on the seats that can be fully customized.

Under the hood of the AMG S 63 Coupe lies a massive engine upgrade made up of new parts, including connecting rods, big end bearings, crankshaft, bearing bushings, a turbocharger, and a suction and compressor system The whole program brings the output from the model’s 5.5-liter bit-turbo V-8 engine to 985 horsepower and 1,034 pound-feet of torque. The extra power helps the AMG S63 Coupe sprint from a standstill to 60 mph in just 3.2 seconds. Unfortunately, all that increase in power doesn’t reflect in the top speed since the car still tops out at an electronically limited 186 mph.

Read our full review here.

Rolls-Royce Ghost "SaRangHae" By DMC Tuning

This one technically shouldn’t count because DMC built this program as a one-off creation for a Korean celebrity. But it’s still a worthy alternative to the G-Power-tuned AMG 63 S Coupe. This program distinguishes itself with a subdued program made up of a reworked front fascia, a straight lined side skirt, a trunk spoiler, diffuser, and rear trim. The interior is fully customizable as owners can pick cabin refinements like leather and carbon fiber.

The “SaRangHae” Ghost also has an engine upgrade that helps the Ghost’s 6.6-liter V-12 engine from 563 horsepower and 575 pound-feet of torque to 632 horsepower and 634 pound-feet of torque. That’s an increase of 69 horsepower and 59 pound-feet of torque. It’s not as much as the G-Power and Mansory kits for the Mercedes, but it’s powerful enough to help the Ghost sprint from 0 to 62 mph in just 4.5 seconds to go with a top speed of 183 mph.

Read our full review here.

Conclusion

The growing number of programs being made for the Mercedes-AMG 63 S Coupe is a good sign that the model is getting a lot of attention from the aftermarket industry. This kit in particular has some nice qualities to it, not the least of which is the engine upgrade and the accompanying price tag. Programs like this don’t come cheap, especially when it comes to a model as expensive as the AMG 63 S Coupe. But it’s nice to see that G-Power was able to keep the cost of its tuning module below $10,000. That’s a really good deal that owners of the coupe should really put some serious thought into buying.