The production version of the Porsche Mission E has been spied undergoing evaluation outside of the company's headquarters.

With the car being widely talked of as a Tesla Model S competitor, it's no surprise to see the Model S, as well as a Model X, in convoy with a large collection of Mission E prototypes.

The new electric sedan was spied wearing a lightly disguised version of the production body, which stays remarkably true to the 2015 concept car.

While the concept vehicle had rear suicide doors, the production car has conventional front-hinged rear doors. The production-intent body also features a larger six side window layout.

There's also gentler arc for the roof and rear windscreen, which should help with rear seat headroom. There are disguised LED lighting units at the front and back, and a set of fake exhaust tips adorning the area around the rear diffuser.

The Mission E should be smaller than the second-generation Panamera, which has grown to over five metres in length in standard wheelbase form.

The all-electric concept car had two electric motors delivering a total of 440kW of power, and a claimed 0-100km/h time of under 3.5 seconds. Its battery pack allowed the concept car to travel over 500 kilometres on a single charge.

In addition to this, the Mission E concept supported a 800V fast charging system capable of topping the batteries up to 80 per cent within 15 minutes.

It remains to be seen how many of these features carry over to the production vehicle.

The rumour mill suggests the Mission E, or whatever it will be christened, could make its debut as early as 2018, although sales probably won't start until later in the year or some time in 2019.