The DLC has been pretty good and was on sale recently. The entire sim is on sale right now.
That said, SMS and accuracy aren’t best friends. The vintage Le Mans track looks sensational but I can pass cars on the grass at over 370 km/h without issue. The lap records are 20+ seconds faster than the real records!
No sim is 100% accurate despite the claims however I find pCARS 2 to be the most relaxed of the current PC sims.
My experience was that different classes feel very different to drive. I can’t judge on authenticity, but instead my on perception and how intuitive they are to drive. In that sense it was a mixed bag and the turning required to make some cars feel more natural was an indication of how bad the stock models were.