I know I'm late but it isn't possible at this time to add in additional clothings such as Nyte Blayde's suit. However, you can still obtain it in a different way. It requires HazardXB36's Saints Row save editor and just only that.

1. Download and install the save editor
2. Open the save you desire to obtain the suit with
3. Extract your character first and then replace your character with this character, save the file after doing that
4. Launch up your game and load your save
5. If you see the same exact character you replaced your character with, go to your wardrobe and save your outfit
6. When done saving your outfit, save your game and tab back to the save editor (you don't have to close out the game to do this)
7. Now replace the character you've replaced with your character, save the file again
8. Load your new save again and voila, you now have the Nyte Blayde suit