I had to replace the fuel pressure gage that came with the GrandPrixStore Adjustable Fuel Pressure Regulator.
It had a Stainless steel case but only a brass tube and connector. Not only did the tube fail and read about 5 psi low but it even started to leak inside the glycerin filled case, turning it dark brown. I could see rust stains developing. It only took 8 months.
The new one is a much better unit using all stainless steel. 0 - 100 psi.
Have it set at 58 psi with the vacuum line plugged and when it'* connected at full vacuum it reads about 48 psi. About 4 psi higher than stock to take into account my increased boost pressure.
The fuel must be corrosive. I only use Chevron 94 Octane.