Whats the effect of changing the diff ratio?

[iRS]

I'm thinking of swapping the diff. It’s been getting more and more noisy. It has done over 200k miles, so no complaints.
I see that diffs from manual diesel S-types are available and have a ratio of 2.69 instead of 2.87. I believe they are more or less the same.
My question is: will the change of ratio confuse the cars' electronics’ systems as the wheel rotations will then have a different ratio to engine revs.
My car is a cruiser, so I'm not worried if its slightly slower off the line.

[mike020150]

Some other questions to add to your list. Would the next owner want a non standard diff ratio? Will you make the necessary changes to ensure ensure the speedo reads correctly? Do you appreciate that Jaguar changed diff suppliers (not the ratios) during the model's run and that may mean changing the half shafts and propshaft to suit? Modern Jaguars have well-chosen gearing and changing like for like would avoid all these issues. Higher gearing may also result in a gearbox which hunts annoyingly between gears at normal road speeds. My advice would be to go for a direct swap from a car with an identical diff and diff ratio to make life easier! Mike.