I actually really like the Rieger kit. It looks really aggressive, especially with those eyelids, and I think it would look really slick in black...and with installation and paint waived, I'd do it in a heartbeat.
I don't know about the AMG kit...i mean yes it does look nice, but it's like you're paying to upgrade the look of your car to a model that you didn't get in the first place. If you get the kit, you'll end up getting the badges and wheels, and nobody likes a poser, right?? [
I'd stick to an aftermarket tuner for that truly unique look.