Well,
I purchased a set of Diablos today for the 748. Not the corsa version as i reckoned i would not need them.
I went out for a gentle run after fitting. Just to get them scrubbed in. I can report that i found them to be very good so far. I have yet to get the the extreme edge of the tyre but they do seem very stable. I will leave the last 1cm of the edge to the hot weather when it comes along for good.