From the Super Mario Wiki
The Lightning Champ is Mario's kart that is found in Mario Kart Arcade GP DX. It is shaped like a Formula One Car, similar to the Sprinter from Mario Kart Wii and the Circuit Special form Mario Kart 8. It has a red body with blue stripes and white lines on it, like Mario's signature overall and cap color. It offers a boost in acceleration performance while not hindering or improving anything else.