Dan, I tapped that boss for the coolant line to the turbo following LandCruiserPhil's method. I did add a shop vac with a small hose sucking up as much crap as it could directly where I was drilling/tapping as well. I used grease to "grab" any aluminum and methodically cleaned the tap several times during the process. The boss is thicker than I suspected, plenty of threads there. Even going slow it didn't take very long at all, maybe 15 mins. The good news is that once you've got it tapped for the coolant temp sender it'll be a piece of cake to just plumb in the line over to the "new turbo"
Special note to Dan - That Acura dual gauge pod takes some MAJOR surgery to fit right! I laughed and called Slee just to check what "a little trimming" meant in CO...
The dremel was priceless for this procedure. Good luck!