well it does exactly what its says on the tin
its a way in which you can make the car really pop out against the background more so than if you were to take a normal shot with the flash bouncing of the celling.
still need to paly around with the right settings but. . .
what you do is take 5/6 pictures, and in each one fire the flash gun at the car so that it lights up that area, so front, bonnet , front wing, rear quarter etc etc depending on what is facing the camera
the in ps just layer them all and it gives the impression of the car being lit like you see in these fancy mags!