Yes, I think 50 ish (46 ish stopped) psi is normal but the gauge can be a big factor.
The "pump running" pressure will be higher because the syphon jet creates back pressure on the regulator. Pump "just stopped" will show the pressure regulator setting. The poor wiring connection (sender/holder connector) can be a big problem. I know the fuel pump connector has turned up as a problem on this forum a few times, I just wonder how common it is, and if the Delphi pump connector is a contributing factor ??

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)