For one, to improve ambience, have the cars' engine sounds to last a lot longer, instead of as it is now, where you will suddenly hear it's sound as it comes along the straight. The BL1 is an example, as you can ''see'' a car coming on the main straight right before you go into the corner at the end of the straight, though the sound isn't there yet untill a certain point.
The same counts for actually seeing the cars. They sometimes just show up out of nowhere, as they come closer on a long straight. (Westhill)
This is quite annoying in my opinion, and it's even worse when you're trying to make a movie.
I guess this was to limit the stress, though with the current pc systems.. i don't really think this would cause a problem. (Except for the 1/10th of people with ancient computer systems)