I have a very good chance on getting a set of HID's from a bmw x5, now, what is involved with getting these to work in my legacy? is there a spacer/bulb holder that can center the bulb correctly? HELP!:(

You have to use HID bulbs with the same type of base as in your existing lights, probably H4. The ones from the BMW will be OEM HID bulbs with a different base and there won't be any way to make them work properly. Even if you could somehow secure them in place the light pattern would be all wrong.
Sorry but that's how it is.

Ok, I have H1's, so that means if I get H1 bulbs off ebay or something like that, they will fit my headlight housing....next, if I do do that, will the wiring from the balasts fit the bulbs? are they all the same?

Mulder is the HID guru here so hopefully he will correct me if I am wrong. HID’s , as used for after market parts, take a OEM HID bulb and remanufactured it to attach a connector at the end. This connector must fit the type of headlight you have. Morettes, STI projectors, Stock etc. So it is not just a matter of H1 or H4 or whatever.

a headlight using an h1 is a headlight using an H1, they are all designed to use the same bulb......think about it, they all go in the same way, they all plug in the same way, they all illuminate at the same point.....the H1 bulb I mean, so therefore the H1 Hid bulb will fit any H1 "hole".....

Not all HID kits are the same, the connectors used from the ballast output to the bulbs vary so you need to match both the connector and the base. It's also rare to find real HID bulbs on ebay, if you do a search on "HID" 99.9 % of what comes back will be "HID-Look" halogen bulbs and there might be one or two actual HIDs. It is highly unlikely that you will find what you need there.