Al right, so I remembered to call someone.
I called the cadillac dealer, they said that its TRUE, you gotta take the bumper off, then taken apart the head lamp assembly!! If I were you, Id let the dealer do it. That way, if they fuck it up, theyll fix it right!!
I thought when you posted them pics and told me you had to take the bumper off, I thought it was the biggest bunch of bullshit Ive ever heard. But damn....that sucks!! Just for a fuckin bulb!!
I also took a better look at that internet "do it yourself" thing. And it looks like the jist of it. But they were doing a HID conversion. So what YOU have to do is not as elaborate as what they were doing!! Just take your time, and write shit down if you have to....I do all the time!!
HRD