Board Thread:Game Discussion/@comment-31.205.20.56-20180521000704/@comment-2405:204:B28E:3186:C1C:78E5:EF13:309-20180521033533

Most probably you have played with this car before during a gauntlet or an SE where it is utilised to get through a stage. You had upgraded it at that time. Upgrades applied to a car (whether the prize car or not) during a Gauntlet/SE/LTS stays on the car until you purchase it.

You needed only to FU the Z4 M for completing Road Car International & the RX-7 for Japanese Production Club. The ROI on RX7 is higher as it allows you to play its exclusive series as well. Save your GC, unless you have got a "reliable source of income".