going back to your first post...
Who balanced your tires??? I ask because I tried a couple different shops (Sears, Peerless) before caving and taking it to the dealership. $88 later, smooth as silk with no vibrations. Cost is a bit much, but it was worth it.
EDIT: I had tires mounted as well, so it shouldn't cost $88. Should be more like $30-$40. Sorry, I forgot to mention that.
It took me 5 months and replacing all of my bushings to track down the culprit. I didn't know it was my tires, because I assumed (huge mistake!) that Sears balanced them properly the first time. I'm not overly bitter, because the bushings needed to be replaced, but it's been a frustrating experience.
You will hear varying opinions on the subject, but; in my experience, it really doesn't matter where you have them balanced if it isn't done correctly.