AFPR's are a total waste of time and money.... if your car is stock. Let's think about this for a moment...
A stock fuel system is controlled by the vehicles computer,
which regulates how much pressure and fuel is delivered to the injectors. If you install a AFPR you can "dial in" the desired amount of fuel/pressure that the injectors deliver..
Sounds simple.. But what if you have stock injectors that are still being controlled by the computer ? The computer is programmed to deliver a set psi, so now that you've got that AFPR installed and cranked up say 42 psi (or more) and the computer say's "no I dont like that" it does not deliver any more fuel to the injectors. Hence your still running a stock system. Now on the other side of the coin, if you to replace your injectors with higher volume and reprogram the computer then there will be a slight performance increse. This is just the tip of the iceberg, it goes alot deeper.
Dave
Guldstrand Motorsports