I bought my car in June and it had 2 brand new Bridgestone RFTs on the back and 2 brand new non run flats on the front, I had all good intentions of changing either the fronts or the rears but just haven't got round to it.
Why ? Well to be honest guys the car feels fine, it handles well, there's no silly swapping ends if I nail it, nothing of the sort. All the cross ply and radial talk is complete nonsense. No doubt the lack of run flats on the front make the overall feel of the front end a little softer, I doubt if it's much though, we are talking about a 30mm tyre wall, it's not going to give a great deal regardless of what tyre type.
What I wouldn't do is put two different tyre types on the same axle, I don't think that would be too clever !