Wait you have an 87 300TD and your door car speaker grills are still intact? This is amazing all in it's own! Let me see if I can find my speaker grills (my door cards are shot, speaker grills and speaker mounts are busted).
These are the perfect drop in replacement's for you car, they are Rainbow products.
I just ordered these from this company, beautiful packaging but I haven't installed them yet. I only bought the front set because I am exploring options on what I should do on the back door cards since they are shot and I do not have replacement door cards at the moment.
Front & Rear W124 speakers are 120mm unfortunately, and if you go to Crutchfield
you get this message. X__X