So I have had my 2014 wrx for about a month and a half. It's at about 1700 miles on it. Two days ago the dealership replaced my spt boost gauge with a new one cause it rattled. Well I noticed now it's going to 16 psi then at 4500rpms it dropped down to around 12. Idk if the gauge is wrong or if that's normal? Thanks for the help and sorry if this a dumb newb question.