I've been using dual scangauges mounted in my ST since I got it. While they did cause the Vehicle Health Reports to fail, unplugging them restored that functionality. While checking if there were any updates available for the Scangauge that would prevent that issue, I discovered that they have a feature in the latest version of the firmware that allows the Manifold Absolute Pressure gauge to be used as a Boost gauge. I sent one of the units back to get upgraded. Those of you looking for a boost gauge and don't want to spend the cash on an Accessport, the Scangauge is only $179.