[elhigh]

You may have already thought of this or mentioned it, if you did then my bad but I didn't see it:

When installing red LEDs to replace incandescent bulbs, the lumen rating isn't a straight-across comparison. Some incandescent lamps in brake light fixtures are a white bulb behind a red filter...and the red filter significantly dims the amount of light that gets through. You might have a few hundred lumens of light coming from the lamp, but only a portion of that actually gets emitted as red light from the assembled brake light.

With the red LED, all of it goes through, or nearly all. So even though you would be down on emitted lumens from the lamp, your performance might be comparable or even superior from the assembly.

Do you have access to a light meter that could compare the performance of the two kinds of lights in the fixture? That's what really matters. Wherever possible if you're going to have an LED in a colored application, get the LED that already emits the color you need. Your wattage will go much farther since you aren't filtering out undesired wavelengths at the lens, and if necessary you can just make the fixture that much brighter to satisfy the CANBUS system. I think - I don't know about that last part, all my cars are old and unsophisticated, just like me. Thank God.