Thanks to all who replied. The wheels have been aligned and balanced. As far as I can tell the flex discs look okay, they are not cracked or deformed. I plan to replace them this spring. I really like that idea of using washers to change the alignment for the u-joints. Thanks Larry. David, It's funny you should mention motor mounts because I was kind of thinking the same thing. That is the first thing on my list to fix this problem. They will be here in a few days. I have owned this car for about a 1 1/2 years and I put about 60,000 miles on it. I absolutely love it. I just need it to stop vibrating.