So I decided to test all three. My setup (what matters of it): Hahn charge piping and intercooler, a CAI custom made from junk, and a Short Ram Air setup, custom made from Spectre Aluminum MAF adapter and filter.

Test was done with an ambient temp of 95* F

-Stock, we all know so no need to put up temp data here.

-With the CAI, IAT1 temps were slightly lower, on the order of almost 10 degrees F. For example, on the 95* day, I was seeing about 97-98*F IAT1. However, IAT2 temps were almost identical to stock +- 5 degrees F, around 98-105 depending on if I was moving or not.

-With the short ram air kit, IAT1 temps were much higher than stock - when sitting still or in traffic. At one point waiting in a fast food line I saw 149*F!! However, with the Hahn intercooler on there, my IAT2's never rose above 100-105.

Driving with the Short ram, I consistently saw 10* higher than ambient IAT1, with almost matching IAT2's (about 10 higher than ambient). This number stayed consistent, even when I went for a drive later that night when the temp had cooled to 70* ambient.


Bottom line seems to be this - In this limited test, using Hahns intercooler (your mileage may vary with the stock intercooler), my IAT2's were always about the same, using cold air intake, short ram intake, or stock. IAT1's varied wildly however, and I was a bit concerned about feeding 145 degree air into my turbo. However the air going into the engine was always about the same thanks to the intercooler.

 

Wow. mine have never risen that high above ambiant (normally within 2-3*) of the stock airbox. I have a couple little mods done to the front of the car that increases the flow of ambiant temp air into the engine bay though. I will agree though when you are sitting somewhere for a while they will go up a lot. As soon as you start moving though they pretty much immediately go back close to ambiant. Better than stock IC FTW.