Just wanted to update that my vibration is gone after replacing:
1) left rear warped rim - still had some vibration after, but it was definitely less
2) right rear toyo proxes ST tire

They gave me remaining-life credit (8/32 & 9/32) on all 4 so I got a new set of Proxes ST II for $250 plus taxes/mount/balance. Couldn't just replace the one since the STs are discontinued in the 315/35/20.

Right away I noticed the steering is lighter. Just glad the problem is gone and I can drive at highway speeds with a smile again. If anyone's interested, I can do a Proxes STII long-term review at some point. All dealers were really negative about the STs in comparison.

BTW, nobody go to AutoTrend in Lindenhurst, NY (also on ebay as 1015f). They sold me the out of round Toyo tire, I brought it back to them twice and they wouldn't admit to the problem. It was an easy warranty claim from Toyo but they chose not to do it. STS Tire immediately saw the hop when being spun on the balancer and did the claim for me. I've spent $500 more than I had to over these months to resolve this whole thing all because they were not honest with me about balance results from the beginning.

Another tip about balancing, ask what speed the balancer spins the wheels up to, because it makes a difference. You do not need road-force balancing to get it right. When I had that done it only went up to 25mph and the vibe was still there at 65. That was a waste of $135.

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'08 X5 3.0si - Alpine White / Saddle Brown interior
Specs: Sport Pkg, Premium Pkg, Tech Pkg, Comfort Access, Aero Kit, Style 433 staggered 20s on Conti DWS
Mods: Carbon 35 tint, LED angel eyes, GP Thunder 7500k fogs, H&R 20mm/25mm spacers, clear reflectors, gunsmoke-tinted taillights
Coded: Digital speedo, windows/sunroof/tailgate close via keyfob

X5 pics at Flickr