Are the NipponDenso compressor any more effecient?

One of my mechanics is finishing up a 617T into a 70's era 230sl. Its an extremely tight fit. Utilizes a ND compressor (custom fitment) which I understand is a better compressor than the R4, just not sure why. Its certainly more costly.

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)