Talk:Jimmie Johnson Championship/@comment-43.247.157.74-20170329115949/@comment-27123099-20170329170558

No, not worth it because if you have intention of obtaining the car, why would you spend more on upgrades than you receive in rewards?

R$ upgrades don't get you to 75% (but you can get over 50%). So, anything beyond that will cost you GC and since you receive only 20GC for the 75% bonus, you'd better hope you sent less than 20GC to upgrade to get that far. Unfortunately, that's not the case.

Do whatever you wish, but several commentors here (many of us with years of experience with this game) will advise against it. It's your R$ and GC though.