[SwissG80]

What I dislike about the ZF GS6 is that the ratios are just terrible. The gap from 1st to 2nd is huge, I feel it really puts the engine out of the powerband (even though said powerband is huge), even when shifting at redline. Similar story with the 2-3 shift.

And then the 4th, 5th and 6th gears are much closer - too close in fact - which really doesn't make sense on a turbocharged car with such a broad powerband! For a high revving naturally aspirated engine like the E92's S65 (which used the same exact gearbox and ratios afaik, as did the F80), sure.
In my mind, the old Getrag 420G in the E46 M3 (and the EUDM 3.2 E36 M3) had perfect ratios. Another excellent set of ratios comes from Honda's K-Series (Type R / Si) gearbox.

And this issue also affects the Alfa Romeo Giulia QV, which uses the ZF S6-53 which has the exact same ratios as the GS6.

One of the things that made me choose the Competition over the standard M3.