I used to have the OE Xenons on my
Ibiza
The D1S bulbs have the high-voltage bits built into the base of the bulb, this means no high-voltage cabling has to run anywhere. I guess this is safer and maybe more reliable.
The ballasts are slimline units built into the bottom of the lamp clusters, made by Valeo.
For washers, you'd need a new bumper (which has the spring-loaded flaps), the washer units & brackets (these extend under pressure and poke through the bumper flaps), various bits of pipework (quite thick stuff, must be some pressure inside) to run behind the bumper, and a different washer bottle & pump (larger capacity - using the headlamp washers regularly uses fluid pretty quickly).
I think the pump just pressurises the pipework & washers with water, and as the pressure increases, the washers extend & then finally spray when pressure reaches a certain threshold.
Not sure if/how you'd get the levelling to work. I vaguely recall someone on here (from mexico??) fitted some OE Xenon units and *think* he got the levelling to work. Not sure how though - given that vag-com reports a Xenon headlight module fitted, there might be another module that needs fitting
Also, there would need to be ride height sensors to know when the car was pitching up/down at the front. I can't remember seeing such a sensor on my
Ibiza but there must have been one somewhere. The Passat one is very obvious at the front.