Pirelli PZero corsas come with lateral wall reinforcement.
This would improve handling under heavy cornering by reducing tyre deformation.
The slightly wider tyres would also give a better looking rear aspect for the car ( in my opinion ).
Standard Pirelli PZero tyres in G are well known for their poor performance and to prove the point; G Superleggera comes with Pirelli Corsas and according to review articles this is helping the handling of the car even more than the slighly reviewed rear suspension stting in the car.

Jondoc