Final update on vibration.

[rallytaff]

Took the car to American Tire Discount, explained the symptoms and they put the car on the hoist. Front tyres are balanced, so no problem there. Checked the rears and the rear driver's side tyre was out of round. Installed the two new tyres and a test drive on the fwy, smooth as you like! Spoke to my alignment guy and told him the problem was solved. He told me that had I told him the whole car shook, he would have told me to check the rears. He's my go to guy the next time. He was correct in his diagnosis! Anyone need alignment in LA, he is Andy's Alignment on Palmer in Glendale. He's the best!

 

[Intuit]

With the stiff stock suspension and low profile tires, out-of-balance wheel/tire combinations are easily noticed.
Took my whip to a hole in the wall place that apparently had little concept of a higher performance tire other than the name and price tag.
After mounting them and rolling them out to my car (with me helping), I had to point out that outside marked wall on three of the tires was on the inside.
Still, because I believe in spreading the money around, tipped them big.
Took'em home, mounted them later that weekend and on the first drive, quickly discovered they weren't balanced.
So next weekend I took them back off again and drove them around to one of the normal tire stores to get them balanced.