plug in chip for an ERST sounds odd...

as for that boost youre seeing, it sounds about right with a std actuator if you were to fit the -31 i'd expect you to see about 7psi with the bleed valve fully closed and upto about 20ish psi when you really start to open it up...

you can only hit 9psi on a non-chipped ECU by the way hence why i say keep the std one...

also i assumed you were using an amal valve, since this isnt as easily adjustable as a bleed valve i tried to simplify things a little (just before sum1 starts picking holes in what i said earlier )