I did not find this glitch founders are:: xDiirty souL and Mocro -DDNL-

Save any adversary outfits tutorial

1. Start an Online Session
2. Open up Interaction Menu
3. Go to "Racing Outfits" if its set to None then tick it to the right and back to None
4. Choose whichever Adversary Mode
5. When you are loaded into Adversary Mode open up the interaction menu and go to "racing outfits" again, then tick it to the right. The selected outfit should be "grey'd" out.
6. After you have done that, open up netflix then back to the game
7. Load up in free mode and save the outfit

Note: Some Xbox users are having troubles with this glitch so I know for a fact its working for PS4 users. For people who want the new adversary outfits but may not have deadline helmet unlock you have to take it off first and then save the outfit for it to work. If you do not set your racing outfits to none then all of the selected outfits will be greyed. Hopefully you guys enjoy!