You want the IAT as close to the TB as you can get it. Accuracy is the key here. If you just want to spoof the IAT readings, you may as well remove it and let the PCM think is -40* all of the time. Since GM based it's IAT calculations off of the fduct location, it is what it is. Howver the most accurate place to have an IAT would be in the intake right before the air enters the CC.
I almost went with the JMB, but after speaking to Justin (JMB) about his aluminized tubing not insulating and actually absorbing heat, a CAI made more sense to me. fwiw Justin in a real nice person, and his FWI it the nicest looking. IMO just not the right intake for me.