Car has 31,300 miles and brand new tires just installed/balanced. Rims checked, no bends. Alignment check is good. Car was built in 2/2014 and in Japan.
There are 2 main symptoms that I'm having. 1st is a persistent vibration in the chassis/floors/seats at highway speeds from 60-80mph. The tire shop says the balance is correct per their machine. 2nd is a wobble felt in the steering wheel under hard acceleration, say merging onto an interstate. It's brief, but definitely there.
My local dealer is pretty useless, so even though the car is under warranty I am probably going to need to use an independent specialist. But does anyone have any suggestions where to start looking?