[Phantom]

I usually place the IAT sensor in the filter this gives the lowest temp of incoming air and allows to have more timing and prevents the IAT a bit from heat soak. With a turbo since the difference in temp is more between filter and TB you might want to place it after the turbo so the engine will not ask for to much timing. Depending on the way the car calculates fuel it might use the IAT to calculate air density and torque.

I would not add a warm air intake to the car till you know what temps you are running currently. How do you have the water injection running?