Well enough money will get anything installed in your car. Seriously though we're not sure. Parts-wise you'd need the cable (which I think only comes as part of the dash/stereo harness, the jack on the console end of the cable, and an entirely new center console in order to have the plug in the armrest. Money wise it isn't really economically feasible, and even beyond that we don't know if there are any firmware differences that make the ACI work in the 2007 that would make it not work in previous models.
Zero Cool is trying to get a hold of a 2007 car to play with and see if the ACI does work in older stereos, but thus far I don't think he's had any luck.
Has Eric said anything about getting the firmware in your AuxMod updated? I'd go that route before I spent a bunch of money on something else that may or may not work. I think next I'd go for one of the other available line in aux inputs. Check the link in my sig. for more of those.
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