i've been reading about this too a bunch. i came across the same problem. idk if the signals are controlled by the bcm or by a flash module. if it is a flash module, can it be changed rather than putting in a resister parallel to the bulb or if its the bcm, it should be able to be reprogrammed to not have hyperflashing when you change your turn signal to a switchback. gonna be making a few stops at the gm store and asking some questions after Christmas.