Have a look at the compressor map.
I had a feeling that was coming. I remember reading how there were inaccurate ones, or possibly mislabeled ones floating around the net. Also, I don't think a comp map is going to tell me about long term reliability.
I have this comp map that is said to be from a BW RS4K04.
I was more looking for real world experiences, of running x pressure over x miles, and how the turbos held up. For instance I saw you mention in a thread that one of your K04's was getting noisy, but no mention if it was BW/Chinese how the car was used, and @ what pressure you ran them over how many miles.