Posaidon Mercedes-AMG GT S and C63 S Pack Extra Punch

While there’s been plenty of hand-wringing about Mercedes-AMG’s switch to an all-turbo engine arsenal, there’s simply no denying that the new M178 4.0L twin-turbo V8 is anything other than a honey of a powerplant. Of course, even in upgraded 503 horsepower S specification (as found in the Mercedes-AMG GT S sports car and C63 S super sedan and wagon), there’s still some oomph being left on the table. Luckily, the Mercedes muscle mavens at Posaidon are here to take up the slack.

Thanks to a reprogrammed ECU, Posaidon has managed to extract an eye-popping 621 horsepower and 535 lb.-ft of torque from AMG’s little “hot V” wonder for the GT S; C63 S owners will have to settle for “only” 603 horsepower, but they’ll also get 590 lb.-ft of torque. Naturally, both models will see sizable (but as-yet-unpublished) improvements in acceleration, while the jailbreaked ECUs will also remove the top speed limiter (provided you have appropriate tires installed): The GT S will do 209 mph, while the C63 S will now touch 204 mph.

And in case you want the world to know you aren’t driving a stock M178-powered Benz, Posaidon also offers carbon-ceramic brakes and the fantastic multi-spoke alloy wheels you see here. On the other hand, with all that extra power and speed, will bystanders have enough time to appreciate them? Something to think about before you place your order.

Source: Posaidon