The addition of a different display screen gives you more data. It does not give you more MPG all by itself. It cannot be considered a "modification" as it didn't change anything. Adding 60 psi to the tires, if that is above the tire's rating ( not Toyota's ) could be considered a "modification".

While the tire psi helps, about 90% of the gains come from driving style.

I can push an advertised 36 MPG Ford Escape to 56 MPG, when I put my mind to it.
All I do is add PSI to the tires ( 48 psi ) and drive better.

-John