[5String43]

I don't know about now, but Car and Driver, at least, used to work very hard to take weather variations out of the performance test variations. The guys had a kit that went everywhere with them that tested temperature, humidity and more. Performance numbers were adjusted, based on what the weather kit told them. It worked pretty well. I know that they got the same figures from a Ferrari (I seem to remember it was) tested in Europe and tested again here in California. They also had a radar gun that they kept calibrated. Probably still do, and more.

I also know that Rodent Track used to be very careful about generating test numbers and went to great pains to make sure they were accurate. I have no idea why they might have differed from those of other magazines, except to note the difference between drivers and driver skills.

Same cars? Probably, at least with Road & Track and Motor Trend, because they were only a few miles apart and drew from the same press pools. But Car and Driver is in Ann Arbor (and for the last few months now so is R&T), and draws from a different press pool. So there would have been variations between vehicles tht could have helped account for performance differences.

Further to this, I suspect that none of us could match the times the magazine guys get in their performance testing. Doing this requires a very special set of skills and a lot of practise, and those guys are good at it. I used to occasionally help out with C/D tests; I've tried to match their times while we were out testing and couldn't do it, especially on the skid pad. Maybe you could, but not me. Frustrating as hell, but there it is.