I can vouch for the Bimmian Spektrum. I have them in my E39 M5, reverse and front turn signal and they really work well and will buy a set for my X5.

On another note I did the led license plate light kit for my BMW E39 M5 and I had problems with getting the right side module to consistently work. I tried two sets and after that I abandoned using them. I got a set of replacement led bulbs from superbright Leds and these have performed well.

So long story short the Bimmian for the Spektrum leds is great but some of the other leds that they market beware.