Today, dialing in a claimed 735 horsepower and 668 pound-feet from BMW's twin-turbo 3.0-liter ... and a further upgrade to a titanium exhaust ($3500). With launch control activated, the Cup ...

So, it’s an M4 with just two seats ... less sound insulation, a titanium exhaust silencer, lighter kidney grille (it’s still giant, but it is lighter), greater rigidity and precision and ...

Nestling behind new carbonfibre front air intakes is BMW’s S58 twin-turbocharged ... bucket seats and dashboard inlays inside. A titanium rear exhaust silencer, meanwhile, brings a four kilo ...