It was totally worth it for the homelink/ temp. It is wired just like you said. The homelink is constant in my set up for th garage doors, the temp/compass is on the ignition. With The correct tool for the mirror it is cheap and easy.
08 GT Vert, Manual, PerfWhite, RedLeather, ClothTop, I-UP, ActiveAlarm, HID's, HeatedSeats, Scoop, Sirius, FoMoNav, 18"PolishedBullitt's, AmbientLights, GentexMirror(Electro/Comp/Temp/Homelink), JaegerFlaps, CPCHoodlifts, CDCWindDeflector, FRPPCAI/Tune, Shelby/Drake STB, JLTOilSep