The BMW Z4 and Toyota Supra are so closely related that the latter wears a sticker saying it was made by the German automaker. That close relationship is nothing new, but it’s interesting to note as an Mk5 Supra was recently spotted at the BMW M Test Center at the Nürburgring.

Tucked among rows of heavily camouflaged BMW prototypes, the Supra sticks out like a sore thumb. However, we’re not entirely sure what it’s doing there as it doesn’t appear to have any camouflage.

This isn’t too surprising as the Supra was launched months ago.  Despite this, it’s somewhat odd as Toyota has previously said the two companies went their separate ways after pinning down certain parameters such as dimensions and hardpoints during the development process.

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If you’re not into theories, a likely explanation is that this is simply an older prototype or a vehicle that was used for benchmarking. That’s far from certain, but the few glimpses of the car don’t reveal anything out of the ordinary.

That being said, BMW M boss Markus Flasch told Autocar that he was open to potentially sharing their new twin-turbo 3.0-liter six-cylinder engine with Toyota. As he said back in July, “We’ve certainly made no offer to supply the engine to Toyota – and no request has been made, as far as I know. But it’s an interesting idea, if unlikely for now.”

While the chances of seeing an M engine in the Supra are pretty slim, the US-spec model has a turbocharged 3.0-liter inline-six that produces 335 hp (250 kW / 340 PS) and 365 lb-ft (494 Nm) of torque. That’s nothing to sneeze at, but the car is less powerful than the Z4 M40i which is rated at 382 hp (285 kW / 387 PS) and 369 lb-ft (500 Nm) of torque.

Picture credit: S. Baldauf/SB-Medien for Carscoops