Quick lowering spring install ?

Hey guys, i'm about to do my lowering spring install and i just want to make sure i have everything I need:

Eibach lowering spring kit (comes with 4 orangish things and i believe 2 black things+the springs.. sorry i dont know what those parts are lol)

Now, do i need to buy 4 of these?

http://store.summitracing.com/partd...908331+4294908282+4294806411+115&autoview=sku

Just want to make sure I have everything. I'll be getting a spring compressor from Autozone as well.
 
you may also need an adjustable panhard bar, depending on the amount of drop. 2 camber bolts are usually enough. those particular bolts adjust for +/- 2* of camber.