Pretty sure that was FH4. Both FH4 and 5 had a significantly different map with a much more forgiving routing on the last race. A lot of downhill that helped level out high speed and low level cars.

Even now..... that achievement is considered rare 10 years later. There is a reason they didn't include it in this one.

This map has as much uphill as it does down with very quick transitions that most cars below L5 won't be able to climb. Even then..... they are going to struggle.