My rule of thumb is, anything below 400whp is ok for a proper big tmic along with other heat management mods. You could heat wrap or ceramic coat the exhaust side of the turbo, downpipe, uppipe and also headers. You could also use a turbo jacket to ad more heat protection. 8mm intake manifold phenolic spacers will help keeping the manifold cooler. Throttle coolant passage bypass mod to keep the throttle cooler if you don't get snow in your area, I don't
. I saw a very well done gold tapeish material being applied to the upper parts of the transmicion and engine surrounding the intercooler, looks cool but I cant say if it helped a lot... that stuff is pricey.
Benefits of a tmic vs fmic, decreasing lag "Over a Fmic", faster throttle response "over a Fmic", no hacking of the front bumper, no rich spikes associated with Fmic "can be tuned out if the tuner knows how to do it". If you want to keep safety up in case of a crash, a fmic is not for you. I manage to cut and reshape my front bumper beam to fit the SSAC intercooler that I had on the sti but still the integrity of that part was compromised. There is an Injen fmic that keeps the front bumper beam but for its size I would just stick with a tmic.
It all depends in your goals and what do you want to do with the car!