So you hate your annoying lack of voltmeter eh? Well check this out.. you can remove your boost gauge and install a voltmeter in its place.
Step 1: Locate NA gauge cluster from junkyard car
Step 2: open NA and turbo gauge clusters, and unscrew 2 bolts holding oil press/temp to the back of the turbo gauge cluster, and 2 bolts holding oil pressure to the NA cluster
Step 3: unplug connector for oil pressure/temp off of turbo gauge cluster
Step 4: Install oil pressure/temp gauge on NA cluster. Plug in the connector where you removed the old gauge connector.
Step 5: replace the screws holding the gauge to the backing
Step 6: Reconnect and reinstall