I hadn't narrowed it down to Kias. I've found drivers in all sorts of vehicles testing my car's capabilities. Of course, nearly all of them can leave a smart behind very easily. But, you can tell when you're being shadowed off a light. Sometimes they're probably just gawking, other times they may indeed be testing an unknown (to them) vehicle.
On the other hand ... I often find that, without even trying, if I'm first in line leaving a light, I leave the pack WAY behind. I know I've got a bit of a lead foot. And, fortuneately, a lot of people are developing a feather foot in response to fuel prices. I need to get lighter.