Yea i watched the whole episode, earler today, and i tell you what, clarkson is a pretty good gt4 driver, cause after the show, i took a bone stock nsx and after 5-6 laps i got my time down to 1:40.3(without tcs and acs) and that was a a pretty flawless lap. So a 1:41 is pretty good. The double apex turn 1 and the corkscrew are tricky. those two turns can be + or - 4-5 seconds a lap.
I would have realy liked to see what the stig good have done around the track in the real car, i bet he would be close to 10 sec. faster than clarkson.