BitetheBullitt0793 (I think that's his screen name) has those springs with Koni's (and a Watts link). He seems to very pleased with it given his past posts, but I don't know that he has pictures. I know that Jim Harris, that's the man who owns the car I have a picture of up on my website with the GT500 springs is also happy. I really like the springs as well.
The Eibach's look good, but they are lower to be sure. Basically the GT500 Vogtlands will take some of the edge off the height. The Eibach's make the car look a lot lower. Suspension wise the taller the springs, the more working travel you have and consequently the car rides a bit better as you aren't getting on the bumpstops as hard or as fast. What is comes down to is mostly the look. If you have to have the Eibach look, then you should go that way. If you want the supsension to be a bit more composed, have a bit more working spring travel and don't want the car as low then it's the Vogtlands. For that matter you arne't locking into the GT500 springs, you can of course use the standard GT springs which lower the nose more (but the rear is about the same).
Here's what it comes down to. Neither is wrong, so don't worry that you are going to create a mess. Just a matter of which is more "right" for your priorities.