I went pre on mine. Like to know what temps are going into the turbo. I tow alot so think it is important. I mounted in the SS up pipe. If you do pre either in manifold or up pipe, be sure to be careful about drill and or tap filings.
The shop that sold me my gauges said not to use grease on the drill bit (as is commonly recommended) because it will heat up while drilling and sling around inside the pipe and capture the shavings. He said to drill dry, then stick a shop vac to the hole and it will suck it all out. He said he follows up with a magnet but has virtually nothing on it.
The technique I used was to drill progressively larger holes slowly one size up at a time until I reached the desired hole size. The shavings stay small and fall out away from the pipe instead of inside. I then vaccumed. That is how the guage supplier I bought from recommended. 30k miles and same turbo, I guess I got all the shavings!
I went pre turbo. After drilling, whether with a greased or dry drill bit, start the truck. This will blow out any shavings in the exhaust manifold. Worst case senario...you blow out shaving from your tail pipe on the ricer who is tailgating you.
I ran POST til i installed my MBRP Turbo Back/Cat Delete and then went PRE.
Its really not frying the turbo that youre watching for...its PISTON MELT...
your pistons are ALUM. & will melt at sustained temps above 1350 <or so>...
Ive never seen temps above 1100 under heavy throttle & towing a car...
and its MUCH easier to regulate the EGT w/ your right foot if you need too.