On the ADTR website it says to specify whether i want the IAT to be close to the filter or not. What is the difference and how much harder/expensive would it be to use the IAT harness.

It'* not really that big of a deal. The IAT harness can be purchased from www.grandprixstore.com or from Thrasher directly. What difference does it make? Not enough for you to ever notice. The first Series 1 intake will be test fitted in my car soon, after that, Hector will start cranking them out to the other Series1 guys. Mine was made per my request to reach from the stock location. I could 'take one for the team' and move it later to see what difference it will make, but again, it won't be noticeable in your foot or on 1/4 mile times. I'm betting it only makes a 5° difference.

approximately how many hp will it add if my car is stock?

Filter alone, maybe 5. Gut your box (see my website) and add more ducting, maybe another 5 for a total of 10. ADTR? I don't know. There'* more benefit to the ADTR than just HP. Torque is an issue, too, and that'* what it was designed for. Yes, I can feel the difference. I felt the filter alone, just barely, and also felt it when I gutted my airbox. I still expect to notice the change to ADTR.....very soon......test fit coming.....

The idea of have the IAT closer to the filter is so that it reads a lower temperature. It makes a difference Willwren, a BIG difference, that is why I offer it. At night time is when you really reap the benefits of having it close to the IAT. I don't offer certain options without a reason and you know that. We are all about performance here, and a little shinniness too. :P But having the IAT closer to the filter did kill my 60' foot be a tenth and the 1/4 mile by a tenth. It does make a difference. :P Learn something new everyday and by testing it at the track with at least 50 passes on my intake alone.

-Hector