The Dodge Viper is a terrible car for just about anything except going rip-your-face-off fast, but at that one, pure thing, it is truly exceptional. So the latest special edition of the Viper makes perfect sense: the 2010 Viper SRT10 ACR-X spec racer.

Built specifically with road courses in mind, the ACR-X offers the best of the Viper ACR with some of the performance enhancements of the Viper Competition Coupe and some extra safety gear. The car is being built for the Dodge Viper Cup spec series that will kick off in July of 2010.

The ACR-X should prove fast--even faster than the stock ACR that set a Nurburgring lap time of 7:22.1, faster than either the Nissan GT-R or Corvette ZR-1.

The extra speed comes from even a whopping 640 horsepower output thanks to new headers and a high-flow exhaust system for the massive 8.4-liter V-10 engine. That's an improvement of 40 horsepower over the standard SRT10 powerplant. It's also 160 pounds lighter than the standard Viper, with aerodynamic upgrades for more downforce. By way of comparison, Dodge says the ACR-X is about 3 seconds per lap quicker around the Laguna Seca raceway compared to a street-legal Viper ACR in the hands of SPEED World Challenge Touring Car Champ Kuno Wittmer.

To keep things safe at such ridiculous speeds, the ACR-X gets a range of factory-installed safety equipment, including a roll cage, fuel cell and race seat.

The 2010 model year will be the final production run of the current-gen Viper, with the car expected to come back only after a hiatus until 2012, potentially with influence from the Fiat Group's performance-oriented brands.

Pricing for the ACR-X kicks off at $110,000, and production will start in the spring of 2010.