Porsche has unleashed its latest 911 Turbo

Porsche is in the middle of upgrading the 21 different variants of the 911 -arguably the greatest sports car ever built.

At the 2016 Detroit Auto Show, the company unveiled the latest variants of the 911- the Turbo and Turbo S.

These are also the fastest and most powerful production versions of the 911 money can buy.

The top-of-the-line 911 gets a host of upgrades including a more powerful engine and upgraded technology package. At the heart of both the Turbo and Turbo S is a more powerful 3.8 liter, twin-turbocharged cylinder engine.

In the Turbo, the engines kicks out 540 horsepower while in the Turbo S, it produces 580 ponies.

Mated to Porsche's stellar all-wheel-drive system, the flat-six cylinder engine can propel the Turbo to 60 mph from a standstill in just 2.9 seconds and a top speed of 198 mph, Porsche claims.

The Turbo S is even faster. According to Porsche, it is capable of sprinting to 60 mph in just 2.8 seconds and a top speed of 205 mph.

The new cars will also feature upgraded aerodynamics, improved traction system as well as a revised engine computer programming to increase fuel economy. They also come with a new infotainment system with a 7-inch touchscreen monitor and Google Earth maps.

The new generation of 911s is dubbed the 991.2 generation, an advance on the previous 991 generation. With the Turbo and Turbo S models headed to dealers, the only versions of the 911 that have yet to be converted over to the newest specifications are the mid-range GTS and the track-ready GT3 models.

Porsche said it hopes to have the transition complete sometime this year.

The new 911 Turbo and Turbo S will be available this April in both coupe and convertible body styles. The Turbo starts at around $159,000 while the Turbo S starts at a tick over $188,000.