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Ok, I got it at 45 PSI at idle without the vacuum line hooked up, when I hook up the l;ine it drops to 38 PSI...is this normal?

 
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Yes.

Boost will increase fuel pressure, vacuum will decrease fuel pressure on a 1:1 ratio with that regulator.

 
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But isn't it supposed to be at 45 PSI at idle?

 
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there abouts yes, so you need to adjust the pressure with it hooked up so its as i recall spec is around 45psi. The stock pressure regulator in the tank has no vacuum source at all to reference. so it should be 45 with the vacuum hooked up. Other wise you could possibly run lean at idle and under modest load. Up to a week a go I had no vacuum line hooked up at all for the past 4? months since i did the return conversion. But now that im almost done with the install i will hook it up and have to readjust pressure at idle to reflect the vacuum source.

 
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I would loose that and just get an emenage. I had one with my setup and it made less power tuned then just my emenage

 
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I THINK you may be thinking of the FMU regulators. What he is talking about is the aeromotive FPR that senses vacuum/boost and when it goes into boost it raises the fuel pressure 1 psi per 1 psi of boost