REVELTRONICS

The intercooler I bought has beem drilled for an air temp sensor post-cooler.

What sensor should I use for this?

The resistance sensors offered in the store dont mention air temp capability, and the digital sensors I am leery of retrofitting to the threaded hole because of the possibility of leaking at boost.

It can measure air temp too but it will be small lag in readings (heap capacity).
DS sensor will be much faster but if you do not have assembling option then you have no choice and need to use threaded sensor.