Tire Wobble Help

Need some advice. We upgraded the tires and wheels on my wife's 4Runner and ever since she is getting steering wobble at around 50mph. Discount installed them so we have had them try balancing 3 times at different stores. I took it to an off-road place last week. The balance was slightly off which they corrected and it did not work. They said the suspension components are good, the alignment is good as well. They told me that the lug nuts on the aftermarket wheels did not have enough thread engagement so we tried another set that have more of a taper/more thread engagement and it helped alot but we still have some wobble. Anybody run into the same issue after upgrading wheels and tires issue and/or have some advice?
Thanks!