Although BMW is usually the first to arrive at the party, this time they're fashionably late.

Although BMW is usually the first to arrive at the party, this time they're fashionably late. Following the Mercedes CLS, Audi A7 and yes, even the Porsche Panamera, prototypes of the 6-Series four-door have finally crossed the spy photographer's lens.

First introduced as the Concept Gran Coupe in Beijing last year, then confirmed for production, and seen in recent leaked patent illustrations, the 4-door Coupe was spotted on the streets of Munich today. Already showing minimal camouflage, indicating the latter stages of development, the wheelbase looks much longer than the two-door 6 Series Coupe while the sleek profile gives way to L-shaped LED tail lights and the ever present Hofmeister kink.

To be marketed as the BMW 6-Series Gran Coupe, there are several different engines which will be offered: two petrols, two diesels, a hybrid, and an M version. This means we can expect a 300 hp (224 kW / 304 PS) 3.0-liter six-cylinder, a 400 hp (298 kW / 406 PS) 4.4-liter V8, a 3.0-liter turbo-diesel with 204 hp (152 kW / 207 PS), a 3.0-liter turbo-diesel with 245 hp (183 kW, 248 PS), a hybridized 3.0-liter petrol with a 54 hp (40 kW / 55 PS) electric motor, and a twin-turbo V8 with 555 hp (408 kW / 563 PS) to 570 hp (425 kW / 578 PS).

The Gran Coupe is expected to debut in Frankfurt this September with a market launch in late 2012.