Jaap,
If you like the chrome of the 230SL but like the other later standard features then you should buy an early (before number 2980) 250SL.
They have all the chrome of the 230SL but have the larger fuel tank (82litres), 4 wheel disk brakes, the later/cheaper style injection pump thermostat, attached soft top handles, plastic covers for the front sub frame mounts, larger/thicker sway bar, six inch wide wheels. The list goes on but these are a few examples that attracted me to my early 250SL.
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto