"It's hard to shoot at something that's left you in the dust. That's the philosophy behind the IO Growl, an incredibly fast-accelerating beast that is guaranteed to out-accelerate anything else on the market. With a high top-speed and impressive drifting capability, the Growl is a great choice for dodging heat or chasing down criminals." In-game description
With the price of $ 400,000 is the only neutral vehicle with 2 modification slots always aviable (ther is no other versions for now) and is the fastest vehicle in game.