After claiming the title of the fastest road-legal BMW ever to lap the Nurburgring with their ACL2 model, the guys from AC Schnitzer are back on the track, possibly looking for yet another record. The German tuning shop has recently posted a video on Youtube which could serve as a teaser of something better to come. In it, we get to see their take on the BMW M4 taken around the Spa-Francorchamps track at full-throttle.

The AC Schnitzer BMW M4 is not nearly as vicious, brutal or fast as the ACL2. The ACS4 has the same 3-liter straight six twin-turbo engine but tuned to deliver 510 HP and 645 Nm (476 lb-ft) of torque, numbers drastically higher than the M4’s standard 431 HP and 550 Nm (406 lb-ft) of torque. That’s not all though, as the engineers over at AC Schnitzer managed to increase these numbers without affecting your warranty or making the car’s emissions illegal.

As a matter of fact, for all AC Schnitzer performance upgrades, the company provides a warranty depending on your home country up to 5 years and up to 120,000 km (75,000 miles) on the assemblies moved by the engine. For M models, this warranty ends at 80,000 km (50,000 miles). The warranty is free of charge, of course, and comes with the products.

The full ACS4 kit also comes with a new exhaust system, of course, as well as a new suspension made up of original AC Schnitzer suspension spring kit for front and rear axle which allows you to drop the car’s ride height by around 30mm. Furthermore, the RS choice comes with individual adjustment of compression and rebound damping. Last but not least we have a new set of lighter, forged wheels as well as some aerodynamic tweaks installed for more downforce, including a wing for the boot lid that was not installed on the car showcased in the video below though.