I thought of getting it just for the outright speed. There's no way a modern LMP car keep pace with a Group C.
That's what many people think but the truth is something else. The pole position for the 1989 race was taken by a Sauber-Mercedes C9 with a time of 3'15 and for the 2013 race by an Audi R18 with a time of 3'22 - and it's worth noticing that back in '89 there were no chicanes on the Hunaudieres.
I conducted a GT6 test on the subject. Using a 908 HDi courtesy car from Arcade mode, grip reduction real, ABS 1, TCS 0, Racing Hards. The top speed is around 342-343 km/h which means that real modern LMPs are slower but Group C cars were quite a bit faster. I observed two checkpoints on the circuit, the first being the one just before Tertre Rouge leading to the Hunaudieres straight, and the second being the one after the tight Mulsanne right hander.
Circuit de la Sarthe 2005 (normal): 0'32,3xx & 2'02,0xx
Circuit de la Sarthe 2005 (no chicanes): 0'32,4xx & 1'45,2xx
If anything, it goes to show how fast the modern cars really go through corners - the real time difference is seven seconds, GT6 shows the chicanes alone being worth 17 seconds and with the modern LMP pottering around at ~320 km/h while the Group C car is doing 400 km/h we would be looking at 20+ seconds. Put them both on the current version of the track and after a few corners the Group C car has no idea which way the LMP went.
EDIT - In 1991 there were already chicanes on the Hunaudieres and Mercedes had replaced the C9 with an even faster C11. The pole position time? 3:31.270...