although you can buy the xenon headlamps ( with bulbs and ballast) for the x1 as a spare part, - the main problem that effects the installation is with the damm coding - moreover the xenon kit comes with the headlight leveling device and the BMW x1 offered for the permit in Sri Lanka is a base version. - so its a strict NO NO...
You can get the part Nos on
www.realoem.com