I have a series II '90 W124 ex Japan.

It came with R12 and I still use it. The car has the dual fan setup and larger Denso condenser. The rear pipes for the condenser fit in O.K.

The trade off is that changing the water pump is extremely difficult. There is very little room behind the pump and above the condenser.

My setup works well. The dual fans only come on when the engine temp reaches 110. or in traffic. The R12 gas in my system is at the correct level. We have over 110 degree Fahrenheit temperature days in summer also.