[BmrBro]

I've noticed a lot more road noise from my Dunlops SP2000s as they wear down.

Is this what should be expected from all Z tires?

 

[Kaz]

Its fairly normal of a lot of modern tires. This is because many tires (especially 'summer' ones) depend on the circumferential grooves for noise cancellation. As the tire wears, these grooves become shallower, and so have less cancelling ability.