I bought a 2012 DGM base WRX 9 days ago. On day # 2, the boost gauge needle got pinned on 5 pounds and then slowly trickled down to zero. I had the boost gauge installed by the dealer (not the factory). I bought the car in a different state.
Anyway, I brought the car to the local dealer. They looked it over and found that the vacuum line was crimped and so it wasn't reading any vacuum or pressure. They moved the line and now it seems to work well. Anyway, first issue for my car at mile 426. Hopefully, there won't be many more.