I looked in the trunk of a 350 and I didn't see any tools, first aid kit or air compressor. My '03 SLK320 had all that stuff. Is it more cleverly hidden in the new cars?

They're located under the spare tire. Remove the spare tire and the pieces sit in a styrofoam holder. First aid kit is in a small black nylon bag, should be with the spare tire.

My first aid kit, is behind the driver seat in a small black nylon bag.