I believe 16" wheels will fit the NA cars, but I'm not sure about the offset.
I would think they just wouldn't stick out quite as far as the stock Crossfire wheels do that's all.
Lots of forum members who drive their cars all year use Mercedes wheels for their winter tires.
I don't think that you'll notice that much difference in the ride and handling unless you really start taking the curves at a higher than normal speeds.
Actually the overall ride will probably be more comfortable because your tires will have more sidewall to absorb the bumps and potholes.