Okay, a few questions. How much boost should my stock 2005 mini cooper s be running? I've read 8, or 10-11..

Second, I just installed a boost gauge and I haven't connected the wiring (I assume that's JUST for the light) but my gauge will show me running boost but then cut back down to show vacuum pressure. I'm wondering if that's from the wires not being connected? I'm 95% sure I installed it properly....