[dradernh]

Originally Posted by Sportstick

With differences in driver skill, tire compound, tire temperature and inflation, weight of fuel and driver onboard, road surface material/temperature, etc.....the results can vary further. But, I am left to wonder why anyone not on a track would care about anything to the right of the decimal? Why don't we just enjoy how the car feels to drive?

Good points, and ones that I'm sure C&D attempts to minimize as much as possible. For example, their tests wouldn't be worth much if they tested an example like this pair while running one car with a gallon of fuel in it and the other fully-fueled. When it comes to tires, though, it just depends upon which great deal from the tire manufacturers BMW settled on for that model and year. You're more likely to read about the effect of tires on performance in their reporting on C&D's annual Lightning Lap event.

As for how much difference it makes, and these are again just my 2¢:

Grocery Run – None
Stoplight Grand Prix – It's unbelievable!
Showing Soccer Moms How It's Done – (do we really need to go there)
Winding Back Road – Some (maybe...depends)
Drag Strip – All the difference in the world
Circuit Track – More power helps; however, many drivers give it all back and then some in the corners