From the Super Mario Wiki
The Circuit Special is an unlockable kart body in Mario Kart 8. The kart resembles a Formula One car, more specifically the ones seen in F-1 Race, another Nintendo game on the NES and Game Boy. It also looks similar to the Sprinter from Mario Kart Wii. In fact, its Dutch name is the Sprinter 2.0, making it a successor to the Sprinter and the B Dasher, which is called Sprinter in Dutch. Its Russian name also means Sprinter when transliterated to English.
It offers a speed and weight boost, but it hinders in acceleration and especially traction; it shares its stats with the Sports Coupe, Mach 8, B Dasher, P-Wing, and Gold Standard. It shares the same sound with the Sports Coupe and is one of the few vehicles in the game to have a supercharged engine, along with the aforementioned karts.
In Mario Kart 8 Deluxe, it is now available from the start. CPU Bowser, Wario, Roy, and King Boo occasionally use this body during races, with Bowser using the Monster tires, and King Boo using the Standard tires, respectively. Pink Gold Peach uses the body with the Sponge tires instead. CPU Lemmy and Luigi are also seen using this kart body, with Lemmy using the Standard tires and Luigi using the Slick tires with the MKTV Parafoil instead. The Circuit Special now only shares stats with the B Dasher and the P-Wing, boosting speed and weight while lowering acceleration, handling, and traction.
The Circuit Special returns in Mario Kart Tour. It appears to be equipped with the Slick tires, based on their appearance in Mario Kart 8 and Mario Kart 8 Deluxe. Unlike before, the kart's varnish does not change depending on the character using it, as it always uses the blue and white varnish. The black, purple, and yellow varnish is instead used by a variant of the kart called the Black Circuit that has identical stats to the original.
Mario Kart 8
Mario Kart 8 Deluxe
The Circuit Special has four different varnish colors. They are similar to the Sport Bike.
Names in other languages