Satan: get the Hella E-codes from here:
http://www.rallylights.com/hella/200mm.asp
They get a bixenon H4 kit from Chris in a 4300K (that's stock for all HID systems), or you can get 6000K's for more bluish white...
Fogs will need an H3 kit in 3000K if you want yellow. Foglight rewire is required with HID's, and you'll need to use a resister to get the high bea indicator to work.
On the MKIV, you'd use HID's for low beam, and a good halogen for the high's (rapid on/off isn't good for the HID's, and HID's have to warm up)
Not sure on the plug style for the MKIV though...