it feels like it needs balance, but I bought new tires and balanced and now seats are shaking and still the vibration at high speed.
I have a 08 toyota camry v6. I had a small vibration at 60mph on 2008 Toyota Camry
DID THEY SPIN BALANCE YOUR TIRES?
If you feel the vibration in the steering wheel (without touching the brakes) it is likely to be front tire imbalance. If you feel it in the seats, it may be the rear tires! Have the rear tires balanced and ask the tire people if the rims are straight and true.