[Locomotive Breath]

Well. I am an electrical engineer. I think that they're saying the electric motor is 95% efficient. That doesn't surprise me. They fail to mention the motor's not the whole system. Which is, as you pointed out, cheating.

[thackney]

I think that they're saying the electric motor is 95% efficient.

From their web site
Tesla Roadster Technical Data

Motor Type designation 3-phase, 4-pole electric motor
Max net power 185kW
Max rpm 13,500
Efficiency 90% average, 80% at peak power

Which like you say does not include losses from charging, discharging, converting and the drive train.