Is anyone aware of a fuel pressure regulator that will fit into the stock plastic fuel rail and have the ability to tell you the pressure?

Yes, Turbosmart has the adapter that fits for a VW or Audi. Then you can run an external regulator and they have that also. I run both on my car. They work great and I also have a Autometer fuel pressure gauge in the dash that is plumbed to the regulator so I can have real time readings as I drive.

Thanks Pilot, Sounds like a nice set up. Where have you found is the best place to mount the regulator?

I put the regulator on the cross bar behind my right shoulder. That way its close to the fuel rail adapter and I used steel braided hose to go to the mechanical fuel pressure gauge (0- 100) in the dash. The 800 series Turbosmart regulator works great and looks good too. I set the pressure at 40lbs at idle or actually with the key on engine off. It goes up about 1lb per boost lb or more.

Did you "T" off of one of the lines between the adaptor and regulator for the return to the fuel tank? Looking at the Turbosmart literature, it did not show a return line to the fuel tank.

Thanks, Frank

Frank, the return line is the same as it was off the fuel rail. The fuel rail adapter takes the place of the existing fuel pressure regulator. The stock fuel rail is still used with both existing fuel lines hooked to it. The fuel rail adapter just makes it so you can have a remotely mounted adjustable regulator.