This is starting to sound like a bit of a thread hijack, but my understanding is that German cars are geared for Autobahn passing, and so are designed for peak torque at 75mph. Hence, around 3200 rpm for the XF.

This was also the case on the A3 12V VR6, which with the stock 5MT was geared at 4200 rpm at 75mph. This got really annoying on long trips. 4200 rpm on a narrow angle V6 with 6 quarts of oil? The coolant temperature and oil temperature on this car was disturbingly high and the fuel efficiency sucked. But it could pass fairly well at autobahn speeds. Hondas with 5 speeds rev about 800rpm slower at the same speed.

I would love a taller final drive too. But what I want more than a taller final drive is a real, honest-to-goodness limited slip differential. Then I could actually use 1st gear without invoking the "gods of wheelspin."