Here was my own take upon the D4's performance curve with the original "noisy whining bastard" pumps I have here. I rang up one of the Laing engineers by phone, forwarded him my results and confirmed with him that my results were accurate to within about 5% of what Laing were seeing. My pump did seem a little more powerful than theirs. Upon testing my second pump I found its results to far more closely match Laing's own testing, so I guess the first pump I got which is measured in the graph below was a bit of a "gem".
