Gabedude, what do you think about this version of your design:
- Use that "ebay" adapter instead of the stock fuel pressure regulator.
- Flop the two rubber hose steel line connectors by the driver's side after the driver's fuel rail
- Run a fuel hose from the "ebay" adapter outlet to the fuel vapor conduit inlet.
-Run a separate goodyear hose to connect the fuel vapors, paralel to the fuel vapor conduit.
-Use a brass T connector to tee together by the factory fuel line in and out ports.
-Install a stand alone fuel pressure regulator by the factory vapor steel line, pick-ul vacuum by extending the vacuum hose from the factory location.
Basically, This above arrangement extends "artificially" the driver's fuel rail "loop", to make it closer in overall length to the passenger side.
It uses the fuel pressure replacement adaptor as a T, then takes the merged return flows back through the vapor conduit and has a fuel pressure regulator in an area under the hood where there's room for it (roughly close to the underhood fuel filter, for a 2002 wrx).
The fuel vapors, under my opinion can be transported through a rubber pipe more easily, less potential headaches there.
The possible downside is that the vapor steel line may be of a smaller diameter, but the regulator may adjust that.