German tuner Posaidon turns its attention to the Mercedes-AMG A45 for the RS 525 that pushes the output to 518 horsepower (386 kilowatts or 525 metric horsepower). With this big boost in power, the hot hatch can allegedly hit 201 miles per hour (324 kilometers per hour).
The RS 525 upgrade gives the A45 a different turbocharger, revised engine mapping, and software adjustments to the eight-speed dual-clutch transmission. After these changes, the total output is 518 hp (386 kW) and 443 pound-feet (600 Newton-meters) of torque. In comparison, a stock A45 S has 416 hp (310 kW) and 369 lb-ft (500Nm) of twist.
Posaidon estimates the RS 525 package lets the hatchback reach 62 miles per hour (100 kilometers per hour) in 3.4 seconds, versus 3.9 seconds in stock trim.
If you don't feel comfortable making extensive modifications like swapping out of turbo, then Posaidon offers a version of this kit that only involves software tweaks. With just these changes, the A45 makes 459 hp (342 kW) and 413 lb-ft (560 Nm). Acceleration to 62 mph requires an estimated 3.6 seconds, and the top speed is 198 mph (318 kph).
Posaidon is also teasing an even more powerful "Plus" tuning package that's still in development. The company isn't providing any details yet, but it's safe to guess that the output is even higher than 518 hp. The firm is also working on other performance improvements, like brake systems, exhausts, and carbon fiber wheels.
As an idea of what other tuners can do to the A45 and its siblings, Renntech offers kits that are capable of boosting the output as high as 592 hp (442 kW) by changing the turbo, exhaust, and engine control software. Without any mechanical tweaks, the company can increase the figure to 469 hp (349 kW).