Restricting the line is pretty much the same thing. I adjusted the one on the 300D up to 11.5 psi by cranking down on the spring about 8 full turns (I had been running only 8-9 psi boost). The way to get the round cover off is to use a big ol "c" clamp and tighten it down on the center of the cover until you can get the clip out then slowly release the spring. The installation is the reverse. Pretty straight forward. I think when I put the engine back together I am going to crank down on the spring another 4 turns
.