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 and the shape of the radiator grille. However, the Rolls-Royce brand name and logo were controlled by aero-engine maker Rolls-Royce plc, and not Rolls-Royce Motors. The aero-engine maker decided to license the Rolls-Royce name and logo to BMW and not to Volkswagen, largely because the aero-engine maker had recently shared joint business ventures with BMW. BMW paid £40m to license the Rolls-Royce name and "RR" logo, a deal that many commentators thought was a bargain for possibly the most valuable property in the deal. Volkswagen Group had the rights to the mascot and grille but lacked rights to the Rolls-Royce