thanks for the replies. i am going to shoot again this weekend. i had planned to use higher shutter speeds (160 - 200th)
i am also trying to convince my wife to drive up and down our street so i can practice - i think that would last about 5 shots
i'm also trying to capture a part of the car (front wheel, front quarter panel etc) and pan with that (sort of like the silver sti in the first pic) - they all turn out blurry though.
regards the feedback about shooting where the car is going to / coming from i have some shots like that, they just turned out pretty bad.