Those wheels look great.

The new BMW M3 and M4 debut on September 23, but the German brand continues to develop them on the road in fairly significant camouflage. Still, these shots offer a close look at the upcoming sport saloon.

The M3 and M4 share a similar nose that includes the brand's polarizing, massive kidney grilles and fairly large openings in the lower corners that offer some balance to the eye-catching nose. The tops of the kidneys create two bulges in the tip of the bonnet.

Gallery: BMW M3 Spy Shots

Our spies are fairly certain that this vehicle is the M3 Competition variant, and the fascinating style of the wheels is among the evidence that this is the hotter model. They have a complicated design for the spokes that's reminiscent of the shapes you'd see in a spider web.

At the back, a tiny spoiler attaches to the rear deck. Two sets of dual exhausts emerge from spaces in the rear bumper's diffuser.

We already know that the new M3 and M4 use a 3.0-litre twin-turbo inline-six. The standard model makes 473 bhp, and buyers have the choice of a six-speed manual or eight-speed automatic. The Competition pushes the engine output to 503 bhp and only offer the auto gearbox.

At launch, both variants will come with rear-wheel drive. An all-wheel-drive setup will be available for the saloon and coupe later. BMW is currently developing the M3 Touring estate but indicates that it wouldn't be production-ready for about two years.