What is (or what should be) the differential ratio on a 260E(or, in the USA, 300E 2.6) model(W124 series)?

On various sites I've met ratios of 3.07:1 or 3.27:1, on another site even 3.92:1.

I'm first and foremost interested in 260E with manual transmission.

~Thank you

Nautilus

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1990 260E Sportline (that's 300E 2.6 for our American friends) -> sold
2001 E320 4Matic Elegance -> my Dad's daily drive
2005 Seat Leon FR 1.8T