The noise difference between the factory Bridgestone and a Michelin PS4 is negligible if any. Utterly pointless to ditch perfectly good tyres sand contrary to what every one says the bridgestones aren't that bad. Driving style has more to do with it than anything.
We can't all be wrong Chris. Quieter, marginally better mpg, massively better traction from a stop (less critical for those with LSD to prevent/minimise tramping), way better turn in grip, better road feel and less choppy ride is what I've experienced with the change - and you don't have to drive like a dick to appreciate the difference.
That being said, although the PS4 are marketed as a replacement for PSS, the PSS are better (softer), but wear quicker.
Even on my Golf R with no tramping issues, the back end was jittery going around roundabouts at moderate speeds.
For my Polo GTI+ (with no LSD), I put up with the standard fit Turanzas until the back end got away from me exiting Testos roundabout as a Golf GTD sailed past me with no drama, on a dry day. Some might've thought it's the limitation of torsion beam rear suspension and a light back end, but changing to PS4 and the car is rock steady and you have to give a hell of a lot more to induce tramping.
Part of the problem is that to maximise mpg claims, over the last few years, official tyre pressures are way too high, which hinders noise, ride and grip.