I am going to take the 9 hour, 9000km and the 24h race and I am thinking on which car I should use, bentley speed 8, mercedes 787B or the peugeot 908 HDi?
i havent driven the 787B but the bentley's rear end will slide out like crazy on tsukuba, im fairly sure the 908's handle the same. For the 24 hours they should be fine, my pick would be the 908 though.
a tiny little wheeeeeeeny bit of challenge, at least for Tsukuba 9h
Go for the 908 or the Speed 8, they're a bit less stressfull to drive. Especially the Peugeot is very predictable, that's a factor if you're in a really long race.
Bentley Speed 8 is still the fastest lap time on my Top Gear Test Track board (I didn't test F1 or X2010). Not sure how well it'd do on larger tracks though...
If these are the 3 cars you've narrowed it down to for the 9hr Tsukuba then be prepared to be bored silly for at least 8:58 of those 9hrs...Instead try a detuned Suzuki GSX R/4 (225-250hp)and have some fun.