Ruphus: Approved LED bulbs are available but are very expensive. Also the LED light source position will be different to the filament position of a halogen bulb which could affect the effectiveness of the housing and/or lens.
This article is relevant;
http://www.stuff.co.nz/motoring/lifestyle-vehicles/78398925/study-illuminates-big-performance-gap-for-car-headlights
Of course the position of the filament affects the output of the lamp. The so called +60 etc bulbs achieve that improvement in a specific part of the beam by getting the filament closer to the ideal point in front of the reflector. An LED bulb might serve as a position or park light but for a headlight would need it's own reflector design.
That article is rat her surprising. It claims the worst performance was BMW at only 36m. Our WOF requirement for any headlamp is 50m minimum. Even though it's an American test and their lighting is not as good as Euro spec it raises questions about the testing.
