Appearence don't have an effect to the gameplay. It only changes your look.
Suits:
- can be purchased for Credits in Dome City at the Armor/Suit/Helm Vendor.
Helms:
- can be purchased for Credits in Dome City at the Armor/Suit/Helm Vendor.
Dye:
- can be purchased for Credits in Dome City at the Dye Vendor.
Jetpack Trail:
- can be purchased for Agenda Points in Dome City at Burning Fashion, and Skyward Jetpacks usually for AP but some for tokens only at Skyward jetpacks.