Looking at LED's for DRL's, Turn, Highbeam, etc.? Have you found truly equivalent light output?

For 'white' lights, the equivalent lumen output that utilizes the original reflector and lens seems straightforward. If the LED version has only 20%, 50%, or 75% of the lumens available, likely that LED won't be good enough.

What about amber (and red in some cases)? When an incandescent bulb for the turn signal puts out 400 - 500 lumens (bulb number 7440 on a MY07), and the lens allows only the yellow/amber range through, what percentage of the light output is thrown away? If 85% of the light from the bulb (red, green, blue, violet portions of the spectrum) then an amber LED replacement of about 70 lumens would seem reasonable. But what percentage of the total white light is really blocked by the yellow/amber lens?