Grainger Avenger

"This vehicle is a modified version of the Hampton Advantage that comes complete with polymer armour and a stripped-out interior to compensate for the weight increase. In short, a fast and aggressive vehicle that should be avoided when and where possible."

This vehicle appears to be, like it's unmodified variant the Grainger Advantage, based on the Rolls-Royce Phantom, albeit with defensive and aggressive modifications installed.

Trivia
Despite the manufacturer being called "Grainger" in-game, the Pursuit Force website refers to the manufacturer as "Hampton" in its PDA section. This is the case with other vehicle manufacturers in the Pursuit Force universe as well, or in some cases the individual vehicle's name.