Hello,
don't adjust only one axle. This is a system with 4 wheels. And these 4 wheels work together. If you want a setup for track i also would recommend to ask somebody who knows what he is doing. And also it will be a big plus if you know what the car should do to support your personal driving style.
If you would have to much negative camber, the inner side of the wheels would wear more or your tire profile would get a sawtooth pattern.
I think it's more a toe problem. But be careful when you adjust toe to 0, because you need some toe in the rear to stabilize the car. Also because of the toe differs on how much the suspension is compressed. Maybe it's not that important in the US where you can't drive more than 75 mp/h. But on the german Autobahn you will be very glad to have toe in the rear above 200 Km/h. And don't forget it's a rear wheel driven car with a mid engine. If you have lowered the car lately you should also adjust the alignment values.
Also some tires tend to wear more than other tires. I don't know these Continental DWS tires, because they are not available in Germany. But maybe they have a harder composite gum and so they last longer.
@jakeru: In general modern tires are directional and have a stamped Outside on the flanks. It's not only the profile it's also the tire carcass that won't allow to exchange tires like you suggested.
Regards, Markus