Be surprised, then: because the 2018 Stinger brochure has no "dynamic torque vectoring" mentioned in the trims descriptions: it only says, "All-wheel drive*". Interestingly, details missing are common: example: Premium says, "Power tilt & telescopic steering wheel". But neither the GT1 or GT2 include that.
That was my primary concern when putting in the thicker rear sway bar. Before handling differences, I was focused on ride quality: obviously in just the first few miles it should have manifested over the same roads. I felt no difference in ride quality. And later, as described, I found the tighter (more planted) feel in the rear a complete justification of the recommendation that, "If you are going to get only one mod on this car, make it the Eibach rear sway bar." And, "This is how the Stinger should come from the factory."
Apparently, changes to the ECS tuning (as per
@Waynerm002's experience with both the '18 and '19 GT2) have addressed the "float"; which would also address the "skipping out" (twitch) on uneven cornering.
As all of this is subjective, each driver must make up his or her own mind on what they feel about the "feel" of their particular stock vehicle.