I was just re-reading Autocar's Road Test Yearbook for 2000, which claims that the Z8 is outhandled by the M5:
"The big let down is the chassis, which not only fails to handle as well as as two-seat sports cars should, it doesn't even handle as well as an M5"
I have never driven a Z8, and I only picked up my 2000 M5 last Saturday (Carbon black/Black nappa). I would be very interested to hear a Z8/M5 comparision. It seems that the best bit of the Z8 is the engine, which of course comes from the M5.
I will post the rest of the (brief) Autocar article if people are interested.
I would add my thanks to everyone on this board for the high quality of discussion here, from which I have learnt a lot and which was a very positive influence in my decision to buy an M5.
BMW take note!