Will I loose my progress/cars when I get a replacement?
You shouldn’t. The game save information is in The Cloud. Recover you gamertag, and you should be all set. However, check with Xbox Support to confirm the procedure.
I had to do this after my son’s Xbox One was repaired. Once you recover your gamertag to the console and attempt to play FM5, the game will automatically attempt to SYNC to get your cloud save. It is possible that the game might create a new save game file when you first play the game. IF this happens, you will get a prompt stating that there is a NEWER save on your console than the cloud save. In this case, choose the OLDER save file (your cloud save will be older than the new save on your console - DOUBLE CHECK the dates/times. Also, you may get error messages a few times because you can’t fully sync. I had to sync 3 times before I could fully get the save recovered to the repaired Xbox One. DO NOT INTERRUPT THE SYNC PROCESS. If the sync does fail, let it fail on its own, DO NOT INTERRUPT this process. Simply try to sync again if it fails to sync the first time. This process made me nervous (his save was over level 400 and had all the cars in his garage short of about 20). Hope this helps.