Still having tire problems

[fullthrottle52]

Problems continue.
My INDY put on a set of bridgestone potenza's (times and tires) on my car and i took it for a test drive. It ran out very smooth. So, I went out today at a very reputable tire store and had them put on a set of Michelin Pilot sports. Took the car for a test drive and the shake again starts at about 69 mph and continues as speed is gained. At about 80 mph you can feel the whole car shake. At 73 mph it is only noticeable in the steering wheel. The manager from the tire store when with me and witnessed the issue. They rebalanced the tires again and possibly made it even worse. My INDY checked the tie rods and everything seems to be very tight. The tire store said that they can not see any wobble in the rims or that would be the obvious problem. I had no vibration in the front before I started this whole ordeal back in August. I am at a loss for solutions. I just thought I would look to anybody here that may have had similar problems before I take it to the stealership and have them diagnose it.

Thanks for any help anyone could give at this point.

P.S. My INDY says that this is the only time he has run into this. Of course it only happens to me.