normally the capusles (bulbs) ant the ballast boxes are 2 separate entities..
so if a bulb were to fade (they loose power/ blue-ness) then technically you could swap up with any capsule with the same fitting , H1 H7 or so on
the connecters are "snap on" anyway, so if the connectors dont match your particular ballast, u can just unclip the old connectors from the original capsules and bobsyouruncle