Great bikes!! I had a couple of DT200's, then a couple of KDX200's, then a GasGas EC200 as my last off-roader. Such great power to weight for the kind of single-track, pine forest riding I used to do.
You are right to consider the jetting - every single one of those bikes was jetted rich [= safe, in the factory's terms] when I got them, and every one really woke up when the jetting got closer to the sweet spot.
They are such fun - the second KDX I had was all dressed up with a graphics kit etc, and looked pretty sharp. They are pretty low maintenance, too, once you get them right...Enjoy!!