just fitted my boost gauge and it reads o.9 bar max in top gears,would like a little bit more like you do ,
so i thought id fit a mbc i bought on abay,once fitted went for spin and got 0.5 bar ,went under bonnet and kept repeating this unti i could no longer turn any more ,WHAT A LOAD OF **** i am now thinking.
did not put little plastic resistor in front of mbc cos of pipe size
sti ver 2

 

Connect direct between Turbo Outlet and Actuator using the shortest amount of pipe possible.
Then Cap off any unused pipes that normally go to the boost control solenoid. Leave the electrical connection the solenoid to connected to prevent Check engine light coming on.

Alternativley buy an 92-96 Impreza ECU upgrade from Ebay .......

 

I just got one off ebay, can't remember what kind right now. I think its amazing the difference is like night and day. Sounds like you have it turned up too high and are overfuelling and engine is coming back down to safe mode at 0.5bar. I tried a duff one and it always dropped to 9psi ( not sure what that is in bar). New one is running 14psi.

Maybe its not fitted in the right place. Mine is a classic so if you want a pic of mine fitted pm me with your email and I'll send you it

Ian