I'll clear the air on this
What I love better about the Tein springs over the Eibachs:
1) The drop is SICK. Better than the Eibachs. Loop is running reduced weight, so the drop doesn't look as dramatic in his pictures above. Let me tell you, I was almost scared after we put the car down off the lift. I'll post pictures very soon. My car is as close to stock as you can get (save the bolt ons listed in my sig). There is ZERO fender gap in the front, and maybe an inch in the rear at the most. I parked it next to my buddy's 350Z, and my trunk is dead even with the back of his hatch. It is LOW.
2) The spring rates are a bit stiffer (if that's the best way to describe it?) than the Eibachs, and they don't require you to do any modification to the bump stops in the struts. I commute to work 14 miles each way 5 days a week, some rough roads, and some highway, and the ride is VERY pleasant for a coupe. Yes, I sacrificed some smoothness, but the handling improvement alone plus the look make it worth it.
When I first bought my 2010, I was very surprised to feel how much less harsh the ride was compared to my 2008 (both were V6 models with stock wheels/tires). I would say that my 2010 SR with the Tein springs rides exactly like my 2008, except lower and less body roll/brake dive/nose lift at WOT.
I'm very happy with them, and I'll be very surprised if the Eibachs continue to sell as well after these hit the market. They are hands down the better set of springs.