Bless your heart it works perfectly.

Advice for other downloaders...
Step 1: Create a plain starter save file by just getting past the intro races.
Step 2: In the WSG folder find the biggest file (should be around 150-200KB) and COPY its full file NAME. Should be something like "D9DB7E783EEE4258B64DD4C5514A1550"
Step 3: Delete that file, and move this downloaded & unzipped 2MB File into the folder it was in.
Step 4: Rename the good File as what the plain starter one was. (Paste what you copied.)
Step 5: Boot Forza, get to the sync screen, chose "Local" which is this new super-god-tier-save, and unfortunately you'll have to sit through that same stupid half hour-at-zero-percent sync thing... but its actually uploading not downloading, and making this special save your official online cloud save. If an error occurs, example, at 98%... hit Continue or Retry. It'll quickly finish. And so you'll load up the game as normal, if youre at Bramburg Castle with an orange pre-order McLaren you know it worked.
Step 6: Fix the difficulty settings, controller settings, character's nickname, and appearance to your liking. Play for a while, or maybe wait till another day/boot of the game to change the graphics settings. (cause screwing with the gfx first thing forces a reboot, you wanna look around and know the save is working first)

Enjoy/