The secret test mule seems to be identified: it was a Porsche Cayenne GTS. That explains the awesome sound!
Based on the Cayenne S, the new model will feature a 405hp (302kW) V8 engine, a lowered chassis and 21in wheels. Though the car’s output pales in comparison to the 520hp (389kW) of the Turbo S, a new weight reduction program and an aerodynamic enhanced bodykit will certainly win it some fans.
The show car will be finished in a new ‘GTS Red’ paint scheme and inside, the rear bench has been replaced with two separate bucket seats making this strictly a four-seater. The first cars should hit showrooms early next year.
Source: Autoblog.nl, MotorAuthority