Board Thread:Game Discussion/@comment-27095714-20160809055110/@comment-28333578-20160811021331

89.121.200.106 wrote: Very interesting... The FXX K exclusive series has 18, 30, 40 and 64 gold for series completion percentages, for a total of 152   gold. I fully upgraded it during the 25% discount, and now I am goint to get some of that gold back.

Also, the R34 has a total 41 gold for completion rewards, and it only costs 3 gold to fully upgrade (+38).

I do not have the other ones fully upgraded, but I expect reasonable return of investment for low and medium PR cars. There is a positive return for the BMW M3 GTS, even if you have no upgrades on it currently. It pays 51 in the series and only costs 31GC. I've long since lost the gold spent upgrading the car for no reason, so basically I get them free. The Ariel is the tough one. It's not needed in any other series, so it has no reason to upgrade it fully, it's a negative. The FXX K is interesting. You have to upgrade it fully for the series, so it functions as a healthy bonus if you have already done that. I can't utilize it because I want to use the 800GC somewhere other than upgrading the FXX K right now.