Has anyone done this? Have an experienced opinion?

BTW, the HEATER and its fan work, in the subject automobile.

I recently inherited a 1980 240D from my Dad. Its R-12 a/c system lost its coolant a long time ago, and I want to replace everything so as to have a system that uses a modern refrigerant... R134a I believe. I found Nostaligic Air-Conditioning systems in Florida, where everything they sell is nominally appropriate for GM, Ford, Chrysler, and also Toyota. To their credit, they have helpful staff and they DO sell "complete systems" which use modern refrigerants. To me that means a compressor, a condenser, an evaporator, and hoses-to-fit.

I don't want funny-looking evaporator plenum showing in the car; I ought to be able to replace the original evaporator coil in the existing plenum... somehow. Ditto the condenser coil, in the usual position under the hood of this car.

Brackets? No problem; I'm good at making "adapters" and other hardware, but I don't want to design any HVAC system from scratch.

Has anyone yanked his original a/c system, and found an appropriate replacement, in any kind of Mercedes Benz?

TIA
John in southern California