The GEM handles the blink function if I'm not mistaken, and there's a little speaker that makes the sound in the steering column.
Most of my exterior is LED and I have resistors on the blinker circuit. Then I found out that the GEM doesn't like having little resistance to the running light circuit. With no resistance in the running light circuit the blinkers didn't work correctly, the opposite side would blink faintly. Plus with the hazards the door chime would beep and the interior lights would flash. So I added small load resistors on the running light side to fix it.
You might be able to not add resistors to the blinkers, but won't get away without having any resistors at all; at least with out a lot of annoying problems.