My situation is:

1)  I already own the McLaren P1 GTR at a PR of 88.7 (16/30 upgrades).  The McLaren Generations Series requires a PR of 94 to reach the last tier, so I’ll need to invest more GC to reach 94.

2)  The wikia site indicated the F1 GTR will likely require a PR of 77 to complete the LTS, which will cost 431 GC in upgrades.

3)  I’m not committed to 100% completion of the game (not yet, anyway).

So, IF (and I emphasize IF) 100% completion of the game is not currently my goal, and I already own the P1, then I’m wondering if there’s any compelling reason to spend GC in this LTS?  431 GC minus maybe 70-80 GC for LTS completion equates to a net expenditure of about 350-360 GC to complete the LTS, for a moderately upgraded car that’s only used in 1 series.

Thoughts?  (Am I missing something?)