The Porsche 911 GT3 is back at the Nürburgring for more development. This video provides an amazing opportunity to hear its engine sing, and the sound is fantastic.

Gallery: Porsche 911 GT3 new spy photos

The test mule in this video wears a little more camouflage than the one in earlier spy shots (gallery above). Up front, the new GT3 features a vent at the tip of the bonnet. There's camouflage over the front fascia, but it appears to have a wider central intake than on the regular 911 Carrera

Rather than using the wide-wing rear that we see on 911 Turbo test mules, the GT3 appears to wear the narrower body from the standard 911.

At the back, the GT3 wears an absolutely huge wing. You can get a great view of its layout in the gallery above. The uprights are on each side of the rear window, and the wing is nearly as wide as the car. The big end plates should make the wing work even more efficiently, too. Dual exhaust pipes exit out of the centre of the bumper. 

The engine making the impressive sound is reportedly a tweaked version of the 4.0-litre naturally aspirated flat-six from the current model. The output allegedly grows from the 494 bhp to around 550 bhp. Judging from the sound of the shifts in this video, it really sounds like this one is using a dual-clutch gearbox, rather than a manual.

The timing for the GT3's debut is a mystery. It's conceivable that Porsche would want to debut the new 911 Turbo first, since the model is the more direct upgrade over the standard Carrera. The GT3 could still premiere before the end of the year, but actual sales don't seem likely until 2020.

Source: Carspotter Jeroen via YouTube