Presumably, the magenta fur would remain that color, although an all-black Super Saiyan 4 Trunks might be pretty cool. While Future Trunks has never been shown using Super Saiyan 3 in canonical ...

Cabba, Caulifla, and Gotenks also achieve the Super Saiyan 2 form, each facing different challenges and opponents. Future Trunks and Kefla master the Super Saiyan 2 form, evolving it to new levels ...