No. There's an unused trace circuit in the tail lights, I believe it's for the rear fogs on Euro spec cars. The bulb in that section is a dual filament, the second of which is unused. That's what I wired up. It's completely independent of any other lighting.
Yea xsperf, I'm not too crazy about the dim area between the two lit up. Guess I'll mull it over a few more days. I'd seen it done on a 318ti, and it looks good.