One Headlight More White Than Hid Color

[amgcrazy]

My left headlight is less purple (HID-looking) than my right one. The car has the OEM HID System in it but I don't know what to do next to fix the issue:

Do I replaced the bulbs alone, and if so, where do I get the bulbs (I want to keep it all 100% OEM).

Or do I replace the ballast and the bulbs?

Thanks everyone.

[1990LS400]

HID bulbs seem to change color as they age. You pretty much have to replace them in pairs to get the same light color. I've seen OEM Phillips D2R bulbs on eBay for far less than what you would pay at a Lexus dealer -- be sure to get new bulbs since there a lot of used bulbs there. The ballasts don't require replacement unless one fails.