That is a nice looking 240D, and low milage. I have the american fuel/oil/temp gauges in my 80 240 and 85 300D. they work great and when I look at it, I know in an instant what they mean. I think those gauges were used up to 79.
I found a couple old Becker Europa Cassett radios for both cars. those newer beckers have 1/2 the owners manual describing how to turn the radio on.
thes old ones, easy, just turn the knob.
I hope your 16 yo appreciates what a nice car this is. If I had a 16 yo, he would have to wait a loooooog time, maybe when he hit 40 or something before driving mine.
Charlie