One aspect of the higher ratio is I noticed this morning it takes longer ( miles driven) for the engine temp gauge to get to normal operating temperature.
Can you also please record the outside temperature during these sections?
And if possible start both legs of the journey with a full tank from the same brand petrol station.
Thanks.
Dan, you can monitor the noise levels yourself - basically note the noise levels at 70mph with your current gearing in 5th, then, drop the revs down (using cruise) to the projected numbers for the new gearset and re-measure the noise.