Vibration

Just got a W reg 145 1.6 runs great except, at about 65mph there is quite a bad vibration felt throuh the accelerator, i cant feel it through the steering wheel but have had all the wheels re bsalanced and i have even rotated all the wheels this made no difference, it feels great up to this point.Also the ride seems a bit harsh is this normal?
Any advice appreciatted

Thanks Russ