What settings for rc shots

[B4 Sloth]

In 2010 i will be getting more into the photography scene. I have taken a number of reasonable action shots but would like to improve. Many have been taken on sports mode which in the main has been ok.
Just wondering what settings u guys use?
The biggest problem i encountered was with focus points. I always used the dynamic area mode but lost a fair few pics as the focus would snatch a photo of something else as the buggy had left the focal point briefly. Is this something i just have to accept, given the small size and high speeds of these cars.

Camera is a Nikon D60, most pics using tamron 70-300 lense