[Woodie83]

The fuel pressure regulator is the square green thingy on top with four torx screws holding it on, it's not adjustable, at least not easily. The screw you messid with first is the proper one, but you shouldn't ever have to mess with it. If your idle is off, something else is wrong.

The weird thing behind your headlight is your cold air intake. It's tuned for sound and designed to remove water from the air. Usually removed for high performance, but the difference is negligable, you might get a little more vroom vroom sound without it.