Speed-TEC built this unique BMW M135i (F20) at their company in Düren, Germany. The company swapped the factory turbocharged 3.0 L N55B30 inline-six for a twin-turbo 4.4 L S63B44T2 V8 from a BMW X6 M (F86). They upgraded the V8 with forged rods and pistons, balanced crankshaft, EU5 injectors, and two TTE850M turbochargers. The motor makes 600 hp but can be turned up to 800 hp for track use. Speed-TEC paired the motor with an 8HP75Z eight-speed transmission and XDrive AWD drivetrain from a BMW F86 X6M. They also upgraded the handling using KW v3 coilovers and BMW F80 M3 ceramic carbon brakes.
Source: Speed-TEC and Evolve Automotive