Rolls-Royce Merlin exhaust flow and waste-gates, meant that this option was rejected in favour of the two-stage supercharger. Fitted with the two-stage two-speed supercharger, the Merlin 60 series gained 300 horsepower (224 kW) at over the Merlin 45 series, at which altitude a Spitfire IX was nearly faster than a Spitfire V. The two-stage Merlin family was extended in 1943 with the Merlin 66 which had its supercharger geared for increased power ratings at low altitudes, and the Merlin 70 series that were designed to deliver increased power at high altitudes. While the design of the two-stage supercharger forged ahead, Rolls-Royce also
Rolls-Royce Motors of the RB211 jet engine. In 1973, the British government sold the Rolls-Royce car business to allow nationalised parent Rolls-Royce (1971) Limited to concentrate on jet engine manufacture. In 1980, Rolls-Royce Motors was acquired by Vickers. In 1998, Vickers plc decided to sell Rolls-Royce Motors. The leading contender seemed to be BMW, who already supplied internal combustion engines and other components for Rolls-Royce and Bentley cars. Their final offer of £340m was outbid by Volkswagen Group, who offered £430m. As part of the deal, Volkswagen Group acquired the historic Crewe factory, plus the rights to the "Spirit of Ecstasy" mascot