Motorsports is partly funded by sponsors and partly by the automaker, one gets advertisements and the other gets to develop prototype features that they can trickle into their production lineup. from the looks of the Honda Ligier JS P2 , I really don't see what they can take from it to use in the NSX.
But obviously information from motorsport to production gets spread around and what not, that's a given. But like @RedNSX said, motorsports is funded by different people. There's technology and hardware that a certain company that's providing sponsorship will put into these cars that production R&D will never touch.