Fuel pressure regulators should always be mounted with an eye toward minimizing the amount of braided line used, as well as for accessibility to monitor and tune the fuel pressure. Ours is on the passenger side of the firewall at roughly the same height as the fuel rails. The left line is our fuel feed line, the right line goes to the fuel rails, and the middle line is our return line. Creating braided line and AN fittings is a pain, but we have to say Aeromotive’s parts may be the easiest we’ve ever used. We didn’t perforate our fingers on the braid once!