Very slight vibration between 50-60mph?

Hi friends,
I picked up my 730Li today and I have to say it's a wonderul car. However the car comes with 17inch rims which I feel is really sad after paying US$220k for my car so I went down to the Hamann dealer and switched to their anniversary silver line rims(275/40/19 and 245/45/19). They are Pirelli Zero Run Flats.
However while driving on the freeway between 90-100km/hr which is about 50-60mph, the car tends to vibrate a little. Above or below those speeds and it's all fine and smooth.

Do I have to run in the car for this problem to disappear? Maybe it was sitting to long in the showroom and the bushings hardened? With my previous Jaguar XJ, it use to vibrate at certain speeds but after a long 2-3hour drive at high speeds, the vibrations totally dissapeared even at those speeds that it use to vibrate. So maybe I have to just run it in?

See if you can get them road force balanced - that might help.

Went down tot he agent today and the chief test driver went out with me for a test drive. He said I'm not the only one who has come back with this issue which is not an issue. It's the nature of the run flat tyres. So we swapped to normal tyres and guess what, no problem at all. I decided to put back my run flats since i paid a little exctra for it anyway. I'm fine with the verdict, I was only worried it would be something else which it was not.

You will need high speed balancing.

I drove up state to Malaysia averaging about 120mph and the car was very smooth. I'll leave it for now.