I recently revisited one of my favourite 1950s pictures, Orson Welles’ Touch of Evil  currently showing on Netflix. It was the first time I’d seen the studio’s original opening sequence with the placement of title cards and the continuous Henry Mancini music.
Great as that Mancini score is (and it really is something, check out the chunky horn and percussion work on the opening number), I do feel that the updated 1998 version - the one remade as close to Welles’ original ideas as possible - is filled with greater tension, greater mystery. Here is the soundtrack to the newly remade opening sequence:
And here is an extract from Welles’ 1957 memo to the studio, outlining how diegetic music is to be used with the carefully choreographed camera work:
I assume that the music now backing the opening sequence of the picture is temporary...
As the camera roves through the streets of the Mexican bordertown, the plan was to feature a succession of different and contrasting Latin American musical numbers - the effect, that is, of our passing one cabaret orchestra after another. In honky-tonk districts on the border, loudspeakers are over the entrance of every joint, large or small, each blasting out it's own tune by way of a "come-on" or "pitch" for the tourists. The fact that the streets are invariably loud with this music was planned as a basic device throughout the entire picture. [Source: Little White Lies]
Walter Murch who supervised the 1998 re-edit comments on this sequence in the following video. Some 25-years earlier Murch employed a similar technique of ‘worldizing’ and mixing together various recordings of music in George Luas’s coming-of-age film American Graffiti .