What to do with pressure regulator?
 

I currently have the stock fuel rails and pressure regulator installed but I have know idea how the vacuum should be connected. Right now I have it routed to the LIM but it looks like the original set up used a solenoid. The documentation I have found so for is very vague on how this is configured. Part of this plea for help is should I even bother with the stock unit? I've seen pic's of aftermarket regulators, is this the way to go and if so with what and how?

There is a nipple coming off the lower part of the LIM, pointing towards the firewall, that is where you want to run the vacuum line from the FPR. Stock there is a solenoid in between, but it is pointless, simply one more thing that can malfunction. Many people remove that solenoid, the FPR just needs pressure/vacuum from somewhere. If you're gonna keep the stock rails there is really no need to get an aftermarket FPR, you'll be fine with the stock one. Are you going to upgrade the injectors?

Primaries are the 550's and the secondaries are 1200's.

the solenoid will switch to vac- source when the map sensor senses boost, so frp will rise the fuel pressure 1:1 with your boost- pressure.
Othervise, it will just beeng closed, so the FRP will read "0hg" making the frp to regulate for about 29PSI of fuel pressure.

-xHg to 0Hg => 29PSI fuel press
0Hg to for example 15 PSI => 29PSI+Boost (44PSI fuel press at 15PSI of boost)

REgards
Iwan