Croatian firm Rimac showed us its Concept_One electric supercar in production trim in March at the 2016 Geneva auto show.

The company is still fine tuning the design, though, and recently provided a behind-the-scenes look at some of the testing helping to hone this 1,088-horsepower steed.

In the above video, Croatian rally driver Juraj Šebalj explains some of the car’s features such as the torque vectoring system, which he helped to develop with engineers responsible for the car’s dynamics and control algorithms.

Rimac has been testing the car at the Grobnik race track in Rijeka, Croatia and recently was also provided access to one of Croatia’s military airbases. In particular, the airbase’s runways were perfect for high-speed testing.

Rimac has previously stated that pricing for the Concept_One starts at $980,000. That might seem steep but we’re talking about the fastest electric car money can buy. The car’s four electric motors see it sprint to 62 mph from rest in 2.6 seconds, pass 124 mph in 6.2 seconds, pass 186 mph in 14.2 seconds and eventually top out at 220 mph.

Incredibly, there’s a lighter, more powerful version of the Concept_One also in the works. This one is called the Concept_S and is promised to offer as much as 1,365 hp on tap.

Rimac is looking to build just 10 cars in its first year, broken down into eight Concept_Ones and the remaining two the Concept_S.

Unfortunately, there's no word on details such as charging times and when we might actually see the first examples delivered to customers.