I have the factory fitted Xenons on mine. I have had the car just under 2 years and I cannot really remember using the pressure wash for really cleaning the lamps. Now I have used them - but mainly for looking good/showing off. The real fact of the matter is that by the time the lenses get dirty the whole front of the car is filthy and needs washing anyway. Besides if you use the pressure wash when the car is clean you'll have those horrible water streaks all over your newly cleaned car.
Furthermore I have removed and replaced both lamps before and I mean the whole unit and it ain't rocket science.
So in my opinion go for the lamps.
Tolahouse 97 E420
Azure Blue - Xenon Headlights
Pioneer HU/EQ/CD, PPI AMPS, MB Quartz Speakers
Brabus 19inch Monoblock5 2pc/245/275Yokohama AVS Sports
H&R Springs/Bilstein Shoxs
"Sound, Power & The Ride"