Why dont you just fit the run flats? Not that much difference in price.
Dont trust the main dealers. My next door neighbour was quoted 900 pounds last week for a new stereo head unit in his 120 BMW. They told him it was a sealed unit and could not be repaired.
I fixed it in about 30 seconds by changing the 10 amp fuse on the rear of the unit that was clearly blown.
Disgusting ripoff service.
The same dealer tried to have me over a few weeks before by servicing my car when it went in for a wheel bearing under warranty!! I told them I didnt ask for a service and it didnt need one so could they please refit all the old filters and put the old oil back in.
They backed down and didnt charge in the end.