A little more on this. I found an article on Yahoo. Here's the link:
http://uk.sports.yahoo.com/040428/4/3iix.html
I can understand wanting to use Herbert for his experience in an Audi R8, which was the reasoning of the team. But why use Turner? Surely Guy Smith has more prototpe experience with stints in an R8 in 2000 and his Bentley drives in 2003.