Vibration on wheels at 140 upwards

Hi Guys

So I've got an e46 320d, currently on 175xxxkm.

All is fine with car, however, when I go over 140km/h, I feel a slight vibration and a loud almost hum/drone when braking. When braking the vibration gets a little worse.

I bought the car like 2 months ago, changed engine mounts and serviced it. The front tyres were worn when I bought it, put on 2 new ones this weekend however the sound is still there.

Any ideas what this may be?