In GTA IV, an Infernus is given to the player as a reward after completing all of Bernie Crane's missions, and it is important that the player must keep it at the yellow box to store it. Otherwise, it will never be seen driving around again, ruining your opportunity.
The Infernus is extremely fast, but is susceptible to damage from high-speed impacts. Even impacts which do little damage can eject the driver through the windshield. Its handling remains similar between GTA III and Vice City, but in San Andreas, although it is the fastest car of the game,(proven by game's data files, top speed 240 km/h), its cornering skills decrease considerably. It is also one of the fastest cars in GTA IV, and a good racing car, but is not as fast as the Comet. According to game's data files, it has a top speed of 336 km/h (208 mph). If you are driving backwards, the Infernus will very easily turn with the smallest movement on the joystick. This can be useful after losing control of the vehicle.
Tests proove that the Infurnas is the fastest vehicle in Grand Thft Auto: San Andreas by reaching a maximum sped of around 170MPH.