Dubai, the relationship between car speed and RPM is direct, mechanical, fixed...

In other words, it wouldn't matter if one 997 was making 330 h.p., and the other was making 400 h.p., they would still do the same speed at the same rpm. The difference would be found in the rate at which they could achieve those speeds under full-throttle.

The only thing we would possibly prove if we all submitted data to you, is whether there's any overt speedometer accuracy varience from car to car.