Boost = heat.
How effective you can make the turbo boost is the key, also think about intercooling aswell. Is a uprated intercooler there? Whats IATs like etc.
Don't just rely on just monitoring the IAT. Place a temperature sensor (just stick it under the hose clamp) after the compressor but before the intercooler. As soon as the temperature of the air leaving the compressor is not linear anymore with increasing boost, but rather exponential, you are starting to push the compressor side too much.
Also, measuring back pressure in the turbine housing is a good idea alongside the EGT.