I'm experiencing body vibration (really noticed through seats) at high speed (more than 190 km/h - 118 miles/h) when the top is up. Anyway, the car stability as good as ever. The steering wheel doesn't transmit vibration either

Four tires are quite equilibrated and I have also checked the chassis geometry

Anyone have noticed this?

It seems anything wrong about car top because I can reproduce it with top down

Any comments will be really appreciated

Thanks in advance