Xenons not always coming on.
 

Just put new bulbs in both lights. The bulbs are from Umnitza(? on spelling). Sometimes they come on fine and other times one or the other does not light right off. I get the check lo beams on the dash. Turning them on and off 2-3 times usually does the trick. Once they are on, they stay on. They was one time where niether light would come on at all.

Everything was fine before I went through the change.

I'm not sure about this stuff, but when u buy anything that isnt OEM, you run the chance of errors like this

There is a Cable you need for the Xenon's Not sure what its called, But I bought the 10,000K HID's and they came with the small digital converter box and i dont have this problem

^they're called resistors..

Is it possible that after long time the xenon have less power? My '00 in the dark need the high beam, otherwise no good light: normal?

I'm guessing the OEM bulbs have a resistor but I didn't see it.

Where is the best deal on OEM bulbs?

there is no resistor in the bulb.

If they are HIDs and the car originally came with halogen bulbs, get a set of these: Error Code Eliminator - 3 (PAIR): HID Kits, DEPO Lights, BMW Bumpers & Lighting - DDM Tuning

However, if the car is a factory HID car, your ballasts could be going bad.

Yes, the bulbs are not made to last forever so that's normal. :D

I think I read somewhere that xenons will usually start looking pink when they go bad. Regardless, replace them or have your X checked out if you can't see the road without using the high beams.

Yep. Depending on bulb manufacturer, they'll start going bluer, then shift into purple, then pink if you haven't gotten fed up at that point, or will simply go dim. 2000-2002 or 2003 have Osram bulbs, which color shift like above. Phillips bulbs simply dim out from what I've been told.

Cimbro, hit up ebay, OEMPlus or somewhere else where you can get Phillips D2S bulbs (part number 85122, or if you don't mind a yellower bulb, 85122+ is a couple hundred lumens brighter) and swap them out. It takes about 45 minutes and you will see a difference. I swapped them in my 02 for new ones and the light is noticeably brighter.