My girlfriend and I saw it in the theater and really enjoyed it. There was a fair amount of creative license taken with it, and added drama, but most of the real story is the engineering effort that went into the cars that would have bored most people to tears.
Shortly after watching it I came across this video about the 1965 Le Mans, which is only mentioned on the radio in the film, and usually gets glossed over in storytelling.
https://youtu.be/iR8FP1_pjn0
I've watched this video a few times because I enjoy the guy's storytelling. He has a few other videos on that channel, and I recommend the shorter one about the Whittington Brothers, whose car is mentioned in the end of the above video. Most of the rest of the channel are guys talking about their exotic cars, which is pretty dull, but there are a couple of other good ones, like the founder of the 24 Hours of LeMons, Randy Pobst, and the guy who found General Lee 001 on a guy's farm in North Georgia.