The Mercedes-Benz 450SEL 6.9 (marketed in North America as simply the Mercedes-Benz 6.9) is the high-performance version of the W116 S-Class saloon. It was based on the extended-wheelbase version of the W116 S-Class platform, introduced in 1972, but equipped with an M100 V8 engine from their flagship Mercedes-Benz 600, uprated to 6.8 litre engine, and featuring full hydropneumatic suspension, licensed from Citroën.
The 450SEL 6.9 was presented to the public at the Geneva Auto Show in 1974 as the successor to the original high-performance saloon from Mercedes-Benz, the 300SEL 6.3 (1968–1972). Like the 300SEL 6.3 before it, the special displacement number (6.9) was affixed to the trunk lid to differentiate itself from the regular 450SEL. The 450SEL 6.9 was produced in very limited numbers from 1975 to 1980.
The 450SEL 6.9 had the first full four-wheel hydropneumatic suspension system from Mercedes-Benz and was the world’s first passenger car to be fitted with a modern form of ABS, an electronic four-wheel multi-channel anti-lock braking system from Bosch, in 1978.[1][2]