wow. major thread revival. thanks for the comments everyone.
instead of answering everyone's PMs individually, i'll just post some general comments here.
1. This is a custom job. If you know how to solder, then you can easily do this mod. Taking apart the cluster is a no brainer. Simply replace the amber LEDs on the circuit board (I believe there are 8) and solder in white LEDs.
2. To get the full M3 'look' effect, I also bought M3 needles and M3 back plates as well. These were purchased used since they cannot be bought separately from the dealer (as far as I know). To buy new, you would need to buy a completely new speedometer, which is very expensive.
3. I did not do this mod. There was someone local to me in the NY area that did it for me. I'm not sure if he is still around, but I do know of another member that started doing this as well.
4. It is not that bright. In fact, I wish it were a little bit brighter. It is not distracting at all. I've gotten so used to them that I had forgotten that I did this mod in the first place. It's only when I get back into another BMW do I realize how different the speedo is. I have no regrets with this mod whatsoever. I think it looks great.
If you want to see a few more pictures: