Maybe a few MPH that was then lost again because of the extra two Hispano tubes and bulges.Talking about very late marks.
They went from the classical supercharger air intake located just a bit behind under the engine to a Mustang-style inlet just right behind under the spinner with the Mk 24, 47 and late Spiteful/Seafang.
How much was the speed gain achieved with this alteration?
Aesthetically it's a guppification/uglification imho.