Su Su got it's name from Astronaut Frank Borman of Apollo 8 fame. It was his bird at one time. He's also owned a TF-51D named Su Su II and a P63 KingCobra.
The marking under the windscreen of SuSu is the squadron emblem for Borman's 44th FS that he flew with in the 50s.
Bill Anders, also of Apollo 8 fame, owns a P51 as well called Val Halla. Anders 51 is marked as a 57th FS bird as he flew with them in the 50s.