What's the cardstock for you ask? Well, you don't want any metal shavings from the drilling or the tapping to get stuck in the turbo, so I separated the turbo from the manifold, and since the whole setup is at 45 deg's with the card stock in there the metal filings just fell right out the bottom! That seemed much more sane than another leading method that involves doing the drilling and tapping with the motor running! eeeks.
Note that putting the sender unit here, I can't remove the turbo mounting bolt with out removing the sender. I would drill further up the manifold next time.
But once that was done I tapped the hole following Jack's advice and it went really well. Thank you Jack for the loan of the tools to do this!
Now we will know exactly when it's OK to shut down the engine!
Here's the finished product, just before putting the heat shields back on:
