User blog comment:SlatBH/Route to Endurance Legends/@comment-36901230-20190927092445

For Zenith Series, I used another strategy. I bought the Zonda R with showcase discount for 320 gold coins and fully upgraded it with R$. Along with the Veyron 16.4, it should be enough to unlock Road to Le Mans and Vertex Spirit.

I have a doubt though, because I upgraded my Veyron to PR 81, above the 80.3 of the R$ Zonda R, and I can't recall if I needed it to unlock the next series. If so, it is an additional 183 gold coins, for a total of 403 gold coins to unlock Vertex Spirit.