What boost are you getting now??? Turn boost controller OFF and you should get nearish stock boost (i get 0.9bar, with BC off fully decatted with nur spec rx exhaust).
Your gain shouldnt be that high, either the restrictor ring is way to small or you exhuast system is too restrictive. (Failing that i guess turbo condition will come into it). Without knowing what boost your actually getting, its impossible to say.....
My gains on 64 at the moment and thats about 1.1 - 1.2bar (depends on air temp, when cold its 1.2, warmer and its 1.1 which id say is a good safe medium)
1. You can still over boost with 1.2bar restrictor ring (or atleast i could!)
2. Without the right settings on BC, mine was spiking all over the place
You only raise your gain, when you getting