You can T into the map line, quite simple. I just drilled and tapped mine into the intake elbow to take a more "stand alone" approach.

Fuel pressure before blue spring should be around 55psi. Ford's actual spec I believe is 50 + or - 5. They say below 45psi is doing damage, but I've yet to see proof. However, I'm not going to disagree either, if it's dropping below 40, something needs to be done. With the updated blue spring, most see idle pressure around 62-67psi. You should obviously test this while driving down the road with some WOT runs too, though if you're having issues like this, I'd suspect you'd see it fluctuating all the time or something.

 

63psi at idle and maxed out at WOT, i got a 100psi gauge ... i think either my gauge is wrong or i missed something ... ugh ... isnt the pressure supposed to drop about 10-15psi at WOT