Vibration while driving ?

99 GT and when driving it feels like the tires aren't balanced. Have had them balanced 3 times. Put new michelin tires on the other day and it seems better but still there. It seems worse when accelerating, the steering wheel shakes like a bad tire would.This is most noticable at 60mph-75mph. On decel it seems to almost go away. I do have american racing rims on the car but they've been on for years.
I was thinking CV joint or wheel bearing.
Has anyone here had any experience with "hub centric" and "lug centric" ? This is when the rim is centered on either the "lugs" or the "hub" Wondering if the rims could be my problem. I've read you can buy a plastic ring to fit on the inside center of the rim to make it center on the hub. It would make sense if a rim wants to center on the studs, as you tighten them it's going to get a tiny bit off center. Dealer says they sell a lot of AR rims and have not had this problem. ???

It sounds to me like you have a bad CV Joint. They usually give you the most vibration when you are accelerating and the faster you go the more the vibration. If you had the wheels and tires properly balanced I don't believe you will have any problems with them so you would need to look at another rotating mass such as the CV Joints. The wheel bearings would make a noise, usually high pitched, and would not vibrate. Have the CV Joints checked out by a mechanic to see if that is truly the problem.