I am having this same issue as well as 12 other warranty issues. I'm taking the SRT in sometime this week to have a second go at getting some of the problems fixed. I'll let you know how I go with the hot air if you haven't already resolved it. Love this car but can't help but wish I got the C63.
Got the jeep back last week and was pretty much told that the hot air blowing is because of heat generated by the motor heating up the air as it enters the car and they didn't seem to address the issue that the air was ice cold if I hit the recirculate button. Sounded like a piss weak excuse to me as that is all they seem to have for a lot of my warranty issues. I am in the process of getting people higher up the chrysler chain involved as the jeep was also supposed to have the transmission update to fix the rough shifts as they advised me to do the first time I took it in for this issue. When I picked it up they said they did nothing to the transmission because there was nothing they can do to fix it even though I have paper work from them from the first time I took it to them asking me to leave it with them for two days so they could apply the update and perform the relearning process. When I showed them their original paper work stating this they just kind of starred at me like I was a time traveler from a parallel universe. I hope you are getting better service than I.
Thanks bro. The head michanic at this dealership is very arrogant and hard to communicate with which makes it even more difficult.
Good luck. I'm sure your guys are much better. The fact they are willing to pull you SRT apart to that degree speaks volumes for their service.