:::Some quibbles, maybe. 
 :::#A cite on "sports car"?  
 :::#Change "closed-wheel" (a term I've never heard); "bodied car" is (unfortunately...) liable to create confusion among non-race fans, so another term is welcome. Same with "closed roof"; if it has a roof, "closed" would seem to be a requirement. (Just use "closed cars"? Or is that another confuser? Are average readers stupid? /) 
 :::#Delete "Gran Turismo", absent a cite these fall into a definable GT class; the early LeMans cars did, up through about the 250 or 365GTB, but I really doubt the prototypes & GTs remotely do anymore, not being (AFAIK) street legal anywhere in the civilized world. 
 :::#Delete the "six times longer"/"eighteen times longer" as generally irrelevant; they're very different formulae. (A mention of the 12h of Sebring or 1000km Nürburgring, maybe...) 
 :::#Mention of driver changes is essential. I'd also say mention of how that's changed would be good, without getting into too much detail: used to be, drivers went the whole distance solo (or, at least, some did; how, IDK 80 ). 
 :::#Mention of how much the distance has changed would be worthwhile: "originally 'x' km, now over 5000", or something. 
 :::#Emphasis on teams is a bit strong; it's common now, but AFAIK, most of the early racers, up into the '60s, were privateers.  
 :::#Finally, in general, the wording needs a bit of fixing, too, but that's after the content is settled. 
 ::: In all, a pretty good start IMO.