since i am only concerned about the z comparo being the cars are very similar:
For an underpowered 4 banger I think those numbers show exactly how great the car is. It is neck and neck with the 350z in every course, yes even the ring, 13 seconds is nothing over 12 miles of track, I personally don't like it for comparisons due to its length and complexity. It takes drivers decades to master that course. Thanks for posting some times in here.
As for your Z, I won't comment, I don't see bench racing getting us anywhere in this argument.
The problem is most of those are tight, VERY technical courses, which is where the S2000 SHOULD shine. Sure the ring is long and complex, but these times are achieved by pro drivers. 13 seconds is A LOT of time even on a 12 mile track. Break that down to your average 3 mile road course and that's over 3 seconds of advantage per lap.
Also found one more on Fastestlaps
2003 350Z @ VIR - 3:12.50
2007 S2000 Type S @ VIR - 3:15.00
That's an ass whopping and it would have been worse for the 2.0L S2000.
I wouldn't comment on my Z either, it's got different suspension, big brakes, and almost 300hp over stock. A stock S2000 wouldn't stand a chance on anything longer than an autocross.