Will the factory void your warranty if you DRILL into the exhaust manifold to install a sending unit?

I heard that they will due to metal particles entering the turbo caused by the drilling.

 

Only if the your EGT probe breaks and goes through the turbine wheel. I haven't heard of anyone having that issue. Drop the turbo down and put a piece of cardboard over the turbo to protect it if you are worried. Plenty of threads on here discuss it.

 

They couldn't just void your warranty for installing guages. How do they know what all you did when you installed them? You may have taken the whole exhaust manifold off to make sure no shavings got dropped into the turbo. As was said earlier, if the probe breaks and takes a turbo out, you're on your own...