Just to share my 2 cents worth.
Most meters are tapped from the source of the transducer or
sensor used to produce 'speed' to the speedometer & odometer.
This 'pulses' has been correctly calibrated by the manufacturer of
the said vehicle.
There's no way to amend unless you are the mechanic.
I am not sure whether the meter 'clock' faster if you do more
than 100.
But I am sure if one changed to a 'under-sz' tyre, you are going
at 100 as shown in the meter, but was actually at 95 physically.
got it?
Anyone tried it before?
My advice to you is NOT TO TEMPT with your Tyres size or
pressure.. Not worth it.. Furthermore, if you get a punctual on
your tyres, you will have difficulty changing it....
especially with the current model of the "last model of the
round eyes", the Rims-nuts are very difficult to be unwise...
Furthermore, the Mercedes has it own "computer" within. It
tracks down the air-pressure and will prompt you onces your tyres
are not in good-conditions... an early warning signal to the driver
(advance techno)... And upon changing tyres... which
normally takes you quite a while.... the opportunity costs lost....
hence, better weigh your options before deciding... good
luck....