Grand Prix Legends was amazing when it came out and the modding/sim racing community kept it alive for an incredibly long time.

However, the version here is not open source, just a demo. Grand Prix Legends also had its share of quirky and odd physics, the fastest drivers sometimes achieved their record lap times with joysticks and took advantage of the differences between game physics and real life.

There have been significant improvements in racing sims accuracy since the GP Legends days, and most die-hard sim racers I know of (including some of the best GP Legends racers) lean toward iRacing as a competitive platform today.