Which One Of These Are Best For Lowering?

The sportline springs drop S197s low enough to degrade the handling a bit, but they look fantastic. They will require the use of an adjustable panhard bar to center the rear axle after the installation.

In general, Eibach makes good equipment. Those Pro Street coilovers are a good way to get adjustable ride height, but their dampening is not adjustable, and I personally couldn't justify spending the dough on coilovers which do not feature adjustable dampening. (like Eibach's Multi-Pro R2 coilovers)

I'm running UPR/Eibach Pro springs* and Koni Sport (yellow) adjustable dampeners on my S197 and they work extremely well.

*Note that my springs are Made by Eibach to their Pro Kit specifications, which means they're not as low as Eibach's Sportline springs.