Board Thread:Game Discussion/@comment-35123883-20180610120605/@comment-2405:204:B188:3024:E4E0:266F:8AFA:1E8E-20180610140601

If you got either PORSCHE GT1-98 or the NISSAN R390 GT1, the F1 GTR is not required for completing '98 Season (Endurance GT Racing). Get both the P1™ GTR & the 720S COUPE to get to around 98% in McLaren Generations without the F1 GTR. Get it the next time it features as an LTS or an FB.

As for 10 lappers, PORSCHE 919 HYBRID (2015) is scheduled for sale as well its upgrades. You should have enough GC to get it. It can be used to run 10 lappers in Endurance Champions. However, IMO the PORSCHE 919 HYBRID (2014) is a better bet (if you're low on GC) as it can be had for free in Road To LeMans & then you can FU it to run the 10 lappers in Endurance Kings till it lasts in the current update & later in the new Endurance Legends career series from 6.4 onwards (not sure if the PR will hold up though).

I personally would get the NISSAN GT-R LM NISMO (2015), if I was in your position, instead of the Porsche and FU it during the sales as it has high chances of featuring in upcoming WTTT.