GuaymasJim asked (paraphrased):

To remove, or not to remove?
The bumper cover is the question.
Whether 'tis nimbler to contort an elbow, wrist & knuckle
Or take battle against a sea of fastners and by opposing, remove them?

Speed is of the essence in temperatures above a hundred.
Please help if you can....
In the heat of such a question, I can only plead ignorance;
Never needing to give new light to that which is dark.

My imagination is exhausted, Jim, please empty your mailbox. Here's my actual reply:

I've never had the need to get to the bulbs. When I do, I'll pull the bumper cover. I don't have small hands and don't want to pull the fuse box bolts.

Don't bother with the forum's search function use your favorite Internet search tool and look for "cadillac forums STS bulb replacement" or variations and you'll find many threads with first-hand opinions from members who have done it.

Good luck.