Please explain spring pad #s

[559EVO]

I hear everyone talking about pad numbers.I understand it is something that I can change but how do you know which ones you already have and which ones do you need.I have a 98 C280 that I plan to lower soon,can I just replace the springs and not worry about pads or how will pads make a difference?

[Renn 208]

http://www.club202.com/forums/showthread.php?s=&threadid=6523

[559EVO]

Thanks