So, why not calculate the improvement in zero-to-60-mph time? Musk said:
"Will use SpaceX cold gas thruster system with ultra high-pressure air in a composite over-wrapped pressure vessel in place of the 2 rear seats.
SpaceX option package for new Tesla Roadster will include ~10 small rocket thrusters arranged seamlessly around car. These rocket engines dramatically improve acceleration, top speed, braking & cornering. Maybe they will even allow a Tesla to fly"
How much do we pick up in acceleration times with these thrusters?
Before we get to that, let's briefly discuss thrusters.
A cold gas thruster is a very simple device. All it does is eject a high-velocity stream of gas. Tesla and the space industry in general use these devices for controlling altitude, roll etc. of spacecraft where small amounts of thrust are needed. Cold gas thrusters are fairly inefficient devices.