These plumbing kits (Comatible with 2008+ Subaru Impreza/WRX/STi) are designed to compliment Radium Engineering Subaru EJ fuel rail installations. Both kits interface with the factory feed and return hard lines in the engine bay (near the LH strut tower) and provide all the underhood fuel plumbing. Both kits are compatible with all Radium Fuel Rails for the Subaru EJ engines (excluding 20-0499 Fuel Rails). All necessary fittings and hoses are included, along with a RA-Series FPR.

RA-series regulators feature the first tool-less pressure adjustment. A jam nut and set screw are no longer required. With a simple turn of the knob, pressure will be increased or decreased. 
To aid in adjusting pressure, there are incremental detents that provide haptic feedback to the user. Every detent permits 1psi (+/-0.5psi) of adjustment depending on current fuel pressure. Furthermore, RA-series regulators feature a 360 degree swiveling vacuum reference port that is double O-ring sealed. This is the first in the industry. It permits the installer to quickly point the vacuum fitting in any direction with no tools required.
There are 4 interchangeable 10-32 threaded vacuum port fittings provided to cover all scenarios. 
1. Barbed Fitting: A black zinc-plated 3/16" (5mm) barb machined from high strength steel that is compatible with the following vacuum hoses: 5/32" (4mm), 3/16" (5mm), and 7/32" (6mm).
2. 3AN Male Fitting: A black zinc-plated adapter machined from high strength steel that is compatible with 3AN hose ends.
3. Push-To-Connect: A nickel-plated brass fitting with Buna-N O-rings that is compatible with hard plastic 1/4" OD tubing.
4. Vacuum Plug: A black oxide stainless steel screw that is used to maintain a constant (non dynamic) fuel pressure. 
 
08+ Subaru WRX/STI Radium Parallel Fuel Rail Plumbing Kit