^^^^ Yea, what he said!
This is a case where the aftermarket is clearly better than the factory original system designed and sold by Porsche. They had no pressure sensor at all, so it could damage a perfectly good compressor by running with little or no refrigerant. It could also keep running when the pressures are too high and the seals all blow.
Like the front condenser fan came with no fuse whatsoever. More than a few 911s burned to the ground because of the lack of fuse. It is hard to argue it is not better to put a fuse in the power wire for that fan. Porsche was in a bad state in those days. The CEO of Porsche at the time, Ernst Fuhrmann, hated the 911 and wanted it dead and replaced with the 928. He forbid any further R&D on the 911 and as soon as sales of the 911 slowed enough, he could kill it. Fortunately for us an American, Peter Schutz, took over and changed that. He personally saved the 911.