I just purchase a 2001 IS300 sport with 18560 mi. During the two test drives I noticed a shimmey in the front end. The dealership had the tires balanced and an alignment done. My wife was driving home and the front end began to shake violently. She pulled over and it stopped. When we got home I looked at the left wheel and noticed a lot of carbon dust on it, I took it out and the same thing happened. It appears to be an intermittent problem.