Well, I just installed my side window air deflectors and I think they look great! They're MOPAR P/N 82208615A and I got them from our great friends at Mopar Supercenter! I'm lucky enough to have bought my 300C form their dealership, so I'm back there often.
I love the short windows, they already look like gun slits and these only add to that look. My only complaint is that they make a little wind noise at speed, but the look is worth it. Just turn up the stereo!
Here's a few pics, let me know what you think!