No it's not based on the Viper, it's not based on a Ferrari either.. It's called the Abflug Schwarzer, it comes from Gotenba in Japan and only one exists in the world. The car is based on a Toyota Supra JZA80 and this not just a cheap conversion kit. It's a bespoke body that is meant to give the Supra a totally different appearance and also the performance that goes with it.
The Abflug Schwarzer is powered by a 3.0-liter six cyliner engine producing 603 Hp and good for a top speed of 313 Km/h (196 mph). The car weights just 1,390 kg (3,064 pounds) and it'll do the 400 meters (quarter mile) in 11.3 seconds.
[Full specs here]