I'm thinking its easier to troubleshoot problems by negating other possibilities. Make sure your wheels/tires are balanced and then get an alignment. The alignment should tell you a before and after settings.

After that if you still have vibrations, then at tleast you know its not the wheels/tires or alignment.

However, I would think when you get an alignment (especially if it can't be set to within spec) that you will discover any suspension problems.

Good luck!