I have a 1999 Saab 9-5 non aero model. Stage 2 tune with stock exhaust. Just installed a boost gauge. Reads at wot 5psi then right as I shift it spikes to 10 psi. The car feels pretty strong through the rpm til 5k then boost falls off. Small turbo and stock exhaust is my guest. Any idea why I'm seeing this? I've tried looking up all this with only a guess that stock my car should put out 6-8 psi. Thanks.