The FD manuals give an intake air temp limit, and indeed have a temp (and pressure) sensor located there! Read your manuals for your turbo engine model you have!! My twin turbo temp sensor has an upper test limit of 176F, so beware things much over that!

The only thing I see is the 176F test point that you mentioned.  I would have to agree that they don't expect you to run that high, but I've seen no "limit" listed anywhere.

The circuitry logic will retard the timing in small increments depending on the temp and the knock inputs, and it cuts fuel to the rear rotor when intake pressures reach 54" hg! PS,

Assuming you're running the stock ECU :-) 

I've got a PowerFC with Datalogit.  I just looked over some logged runs from the car, and never saw anything over about 115F for air temps (about 50F ambient).  Unfortunately, the intake temp sensor is very nearly useless on an FD, since it tends to read the temp of the aluminum manifold rather than the air.  The Commander display for the PFC shows intake temp, and I can't make it change even one degree with a 15-20 second 5th gear pull at 10 psi.  When I stuffed a thermocouple in the turbo outlet of the turbo on the plane, it changes immediately, as it should. 

you can get the stock FD intercoolers for a song (Nylon end tanks, alum fins). Maybe even the TI and TII previous intercooler models as well. They are sort of in the same category as the ac coils. You don't need much intercooler airflow at 140kts to really cool that intake charge. Do your test with that intercooler with the proper airflow thru it as well. Standing still your engine will heat soak while running.