~80-100 when hotlapping with every setting maxed out.
probably a minimum of 30 in T1 online, same settings, smoothes out to 70-90 during the race. Either way it never becomes overly jerky and certainly not unplayable, ever.
3200+ @ 2.2 Ghz
1GB Ram
X800GTO2 with unlocked pixel pipelines, default clock speeds
Either way it doesn't seem to be a very demanding game, my system is very mid-range these days.