Board Thread:Game Discussion/@comment-77.186.79.220-20170806121319/@comment-27048832-20170806153636

P1 GTR < no gold need to be spent to unlock next series, also this was voted to be the best car in the game (before Le Mans 2016 update)

2015 911 RSR < again this car & the Renault don't require any gold spending to unlock next series (although I do remember being stuck with only the Renault not being able to unlock teh 911 showcase) maybe include the Aston Martin making all three cars in Racing Spirit required

A Group C car (doesn't matter which one, they can all unlock next career series alone)

Agera R < no gold needs to be spent to finish up Zenith Series, it is an expensive car but it has many series to be used in, this also allows showcases to be obtained for other cars within those series

I can't comment on Vertex Series I got lucky and bypassed it when I finished Road to Le Mans