The most I have ever seen it spike to is 15psi. Hopefully my self installed boost gauge is accurate.
To get 10-11 psi it may spike to 12 psi at the most but I don't really have any spiking issues.
A couple of times (while tweaking the boost) it's gone up and held in the 13-14 psi and if I go WOT and start accelerating all of a sudden at higher rpm I'll hear a thud and it feels like I just ran over a moderate sized pothole. You know that sort of jarring feeling. Any ideas? Wheel hop... or much worse? Acceleration while boosting that high is awesome though.