I am a Formula E fan and this is my first review:
At first, grip feels right, so, good work :D
As you mentioned, sound outside is missing.
Sound inside is present but not that realistic. rev 0 to 'idle' is nearly missing.
Gear ratio and the engine are problematic.
I don't know, if this version had 5 gears. I know, they have one gear or 2 or 3 this year and last year.
Biggest Problem is the torque. The car accelerates much worse in last gear than in lower gears and that's not correct for an electric motor, I think... Especially at low speeds (e.g. 50 kph), this car should accelerate like a rocket, even in last gear. So try to change the torque curve. Maybe, there are official values somewhere. Idle should not exist for EVs, don't know if AC supports that.
Last but not least: This car is electric. AC supports electric motors already (see hybrids), it's not perfect though. You could analyse the 919 Hybrid for impressions.
In my opinion, Kunos should expand their hybrid system to support electric cars. Who knows, maybe they release their own electric car :D