Good question!
The issue at the moment collecting data, is that it's only really any good if it's equal cars for comparison.
Knowing the power of car x is 10% lower than car y when the lap times are the same, shows it was actually a better lap by driver x with "inferior" machinery.
This means trying to predict possible lap times will always be out in career mode if it's compared to historic equal car data.
I suppose it depends how the game engine is affected by the different parts, thus, after collecting enough data, you might be able to tell that upgrading the wing could knock off x seconds.
Or be able to normalise lap times.
As it is in career, you don't know if the car has got better, or if the driver has in later seasons. You're not really comparing eggs with eggs. :-)
I generally stay away from career for those reasons and it appears I'm weird and love playing with collected data. Haha!