Some years ago I did some rather extensive testing and plotting of the output of various bulbs for the BMW Car Club magazine Roundel. This included the high-output Osram bulbs. Daniel Stern was a great help in this testing and article. The testing took several months to complete (working steadily at night..)
Some quick conclusions (I only tested the +50 bulbs in the higher-output bulbs, I also tested HIR bulbs - Google them - HID conversions and about 10 different halogen bulbs.):
- The Osram Nightcutter +50 euro bulbs DO put out more light then a standard bulb. They put out more light then the Sylvania/Osram Nightcutter bulb sold in the US. The US version has a bit of blue coating so the color is different (and not actually what you want) The tradeoff with a high-output bulb is a shorter life. The filament is wound tighter and burns hotter. Current consumption (IE - AMPS) is the same as a standard bulb. (FWIW Watts = Amps x Volts and using "Watts" to measure light output is really questionable since different bulbs produce different amounts of light when drawing the same current at the same voltage.) Real measurements use "FC - footcandles, or Candella, or Lumens" - all are measures of the quantity of light. Also significant is how useful the light is - ie - the pattern. That changes with bulb type due to differences in how the filament, or arc (for an HID) is shaped.
- Some of the blue bulbs, including one very large aftermarket* brand's version put out less light then a new standard halogen bulb. Blue coatings are an immediate sign to me of marketing over performance. I'd avoid them.
- As someone pointed out - bulbs age. Replacing an old halogen with an identical new one can increase light output about 20-25% with no other change.
- HID conversions can blind oncoming traffic, which is never a good thing. HID specific headlights are designed not to do this.. the halogen headlight converted to HID will not be optimal for the HID light source. I know people will say they never get flashed, or it doesn't make a difference, but I agree with Daniel Stern on this - it's really a questionable practice. IMHO - if you need that much more light, consider auxiliary lights which can be setup to switch on with your highbeams. You can aim the auxiliary lights so they are useful and fill in spots where your headlight doesn't reach.
* the aftermarket bulb brand starts with P, has 4 letters and ends with A..
Your Lumens May Vary..