Shutter lag: I have Canon EOS3, my brother has D20 and I have friend who has D5. No noticeable difference between mine film and their digital cameras. Ok, maybe some computerized measuring machine will measure difference, but I didn't see it.
Autofocus: I usually (90%) of time use manual focus. But, autofocus worked with basketball play shooting, car rally racing, and I didn't have oportunity to try it with formula 1 race, but I belive it will be no problems. And it was on slow lenses. What I want to say, if you use cameras as good as EOS 3 or even faster, autofocus works good, so it is up to you if you want to use it or not. If you don't get good photographs with autofocus with these class of cameras it is up to you, not camera.
Five days ago was concert of Paco de Lucia in my town. It was really sad to look at people with theire mobile phones and digital p/s trying to get picture from 50 meters distance...
I had Olumpus mjuII. It was stolen from me. If I can find another one, I will buy it. Lovelly little sexy thing.