so lately the bulb on my passenger side seems to go on and off when it feels like it and almost appears to be a diff colour. is this more likely a ballast issue or a bulb issue/ any suggestions? i think the car is just mad at me because shes been phased out for an STI

sounds like bulb issue if it is a different color

Swap out sides and test again. Thats easiest way to find out what the issue is.

HID bulbs usually change color before they die, replace the pair so they match.