I have only put 93 octane in it since I bought it..
With regards to the CAI I bought it off CL from a guy who had it on a 2011 GT also. How can I tell exactly what model CAI I have? I think when I filled out the Steeda tune request form I just put Steeda race CAI since it did not have the MVT tube. It has not made any noise since and no Check engine lights are on, but it definitely made some loud weird sounds when I first cranked it for about 2 minutes.
The tune has to match the MAF tables or your car will think its getting more/less air than it actually is and the engine will at best run poorly and at worse damage itself badly. It needs to be very specific to the model of MAF that you have.