The winter testing season is in full swing and our spies have managed to snap new photos of the 2015 BMW 7-Series.

The winter testing season is in full swing and our spies have managed to snap new photos of the 2015 BMW 7-Series.

Dressed in swirly camouflage, the redesigned flagship has an evolutionary exterior with similar proportions to its predecessor. The styling details are hard to make out but we can see the model will a rakish windscreen, a more dramatic roofline and a stylish dual exhaust system.

BMW has remained tight lipped about the model but it is expected to use a variety of lightweight materials including aluminum, carbon fiber and high-strength steel. These changes could enable the sedan to weigh 450 lbs (204 kg) less than its predecessor.

It's a little too early to forecast the engine lineup but previous reports have indicated the model could be available with everything from a 260 bhp (194 kW) four-cylinder to a twin-turbo V8 with 475 bhp (354 kW) and 480 lb-ft (650 Nm) of torque.