Creaking noise when braking, especially in colder weather

Every year, when the weather gets colder, my 89 560SL with 173k on it starts making noise. It happens when I come to a stop and is directly related to the front of the car dipping down a bit under braking. I can hear it in the cabin quite loudly, and it seems to be emanating from somewhere around the footwells. If I pulse the brakes, the creaking pulses too. It's loud when heard inside the car.

It never happens in the warm weather, and sometimes after driving for a while in colder weather, it will disappear when the car warms up a bit.

Common sense tells me its my suspension, but I don't know if it's the struts, springs, or even something related to my ball joints or control arms.

I've owned the car since 122k, and have never invested any time or money into the front end, except for one steering box adjustment 5 years ago. She's a little loose up front now, and most of the rubber parts are cracked and/or missing. I need to get it done now, but with this creaking noise, I'm wondering if I need struts and shocks.

Anyone know about this noise?