From Maserati monthly;

This is the new Sport GT, the edgier Quattroporte for those who want even more performance from the sports sedan that evo says “redefines big car handling”. evo blasted a Quattroporte around their test track in less time than the V10 BMW M5, proving the Maserati is the fastest real world sports sedan available. The new Quattroporte Sport GT ups the ante with even better handling and a brilliantly engineered concentration on usable performance.

click here for the full article