also from an artistic standpoint, in order to reach that look you take the photo of the object in motion, but you must be in correlation with thier direction and speed.
for opposite affect take the picture stationary and target the back ground and the object will look like its moving.
most high end cameras can compensate this on thier own given you know how to set them up, but if you have an average camera, this is how you can reach the desired affects.
awesome...I was gunna go out later and take some pics with my friends GTI and my car so I just wanted to know exactly what to set the shutter at...im shooting with a Sony a300 and my friend a rebel