What do you mean by save ID
Also, I did a lot of stuff today regarding Mii Fighter costumes, but especially I managed to figure out something very stupidly simple; here is a compilation in the form of a screenshot
http://prntscr.com/8ey3e5.
I also found the specific codes for all the Mii Fighter outfits that are obtainable without money; it seems like they are all even EXCEPT FOR the last one on the list:
00 - Brawler Base
02 - Swordfighter Base
04 - Gunner Base
06 - Brawler Protective Gear (I think, see previous)
08 - Brawler Fighter Uniform (tested)
0A - Brawler Tracksuit
0C - Brawler Biker outfit
0E - Gunner Fancy Suit
10 - Brawler Mech outfit
12 - Swordfighter Ninja outfit
14 - Swordfighter Samurai armor
16 - Swordfighter Plate armor
18 - Swordfighter Cybernetic outfit
1A - Swordfighter Neon outfit
1C - Brawler Vampire Garb
1E - Gunner Mage outfit
20 - Gunner Steampunk outfit
22 - Gunner Wild West outfit
24 - Swordfighter Pirate outfit
26 - Gunner High Tech outfit
28 - Gunner Dragon Armor
31 - KK Slider outfit
Today has been a stressful day of staring at a crappy hex editor