Interesting thread; I'm contemplating a ScanGauge as well. The other thing I'm considering is the PLXDevices DM-200 60mm Gauge, which uses the OBD port as well:
PLX Devices Inc. - DM-200 OBD II 60mm Universal Gauge
Can I ask where you have mounted the ScanGauge? It's nice and small, but would like to learn where you find a safe location to mount it. I ran across this GPS mount that offers different mounting adapters... if I get a ScanGauge, I'm tempted to use this in combination:
KUDA mount and holder MINI - MINI COOPER (02-06)
(there are two pics, its the bottommost one)
thanks for any suggestions or perspectives!