This thread shows the effects of Project Drive:
https://www.the75andztclub.co.uk/for...ad.php?t=34369
There doesn't seem to be many that would have a significant affect on noise levels.
Maybe sound deadening levels were reduced without much disclosure.
Certainly tyre noise varies between brands very significantly, up to several decibels. That's quite a difference. Some tyre distributer sites list the decibel levels of each tyre they sell. Check out the MyTyres site for example.
TC