First of all: :becky:
Dunno if hei is from Germany, as feather and spring are the same word in german.
Switching springs is easy enough, unless the switches are plate mounted.
[video=youtube;GivKt63dLvA]http://www.youtube.com/watch?v=GivKt63dLvA[/video]
Video was
shown to me by sordna and made changing the Cherry MX brown keys on the thumb cluster of my Kinesis Advantage a lot easier than resoldering.

As for the effect of replacing the spring in the brown switch with one from a black, the Wiki might be of help.
Update: I guess I took a while posting, sorry for the redundancy.
