Turn Signal Switch
On my '72 CS the turn signal switch failed, as did a second-hand replacement, and I didn't like the high/low beam switch function (up/down rather than towards and away from the wheel) also I prefer the wiper controls all up on the control stalks, so I rewired with 73 onwards switches from an E3 I used for spare parts. I believe the part numbers are the same as 73 onwards coupes. I expect good quality second-hand ones can still be found. It's possible to do the wiring into the various CS plugs without cutting or changing the main loom.
The result is that the switches' operation is the same as later (E28 is as new as I get) BMWs and current European cars. (left hand is turn signal and high/low; right hand is wiper on/off, wash and speed selection) The later switches also feel more robust to me. I drive the coupe infrequently, so it helps to have the controls work like my everyday car.
Because the job took a couple of days to work out and do, I wrote it up, however on rereading over a year later, I realise it needs clarifying. I just happen to have a pair of brand new switches I'm about to fit, sometime, so will add some photos.