You may want to review the articles at the following links - 3 independent tests which confirm the physics of why you can't wind up with more total light output by filtering out some of the visible light to get a blue bulb. You CAN, however, redesign the filament arrangement to concentrate that light in more usable areas, with less scatter, for a more efficient bulb.
IMHO, you migh want to try the Philips Vision Plus with the repositioned filaments (see tests). You may also want to install the relays and heavy guage wiring which will optimize the performance of any bulb you choose by insuring maximum current to the bulbs. Enjoy your Euros, they are great.
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