Thanks so much for the detailed guide, a lot of it didn't make sense until I was under the car doing the install, but it came out great! I made it an additional brake light and think it just looks amazing. And the one I got isn't brighter than the rest of the brake lights, something I was worried about.
I got mine from
Z Car Parts.com -- Motorsport Auto -- Home
Here's a quick vid I grabbed with my phone.
And a pic: