I don't really understand Eva's move with the spirit though. Sure, Air spirits are the fastest of spirits, but they don't go that fast. Had it been at another hour in the center of downtown, it could have been to avoid the jams, but here, the car should go much faster. And given the probable size of the buildings, she'd have to fly over them to go faster, which would make her more visible.
Given the absence of rolls, I'll suppose that it's a Force 4 spirit. This means that its movement values are 14/28.
28m / turn translates to 33.6 km / h. If it tries to sprint, it will get an average of two successes, which means it goes up to 57.6 km / h.
The only solution I see would be to have the spirit use its movement power, then it would go up to 230 km / h. Much better (a bit too much though, you'd probably need to have the spirit use it's guard power on you...) but it starts to be a lot and the use of the power would leave a consequent signature in the astral and effectively signalling that you're coming (as would the invisibility spell and the spirit itself in the astral anyway). If they have a mage on overwatch, it's dangerous...