educate

I own a couple of KTM's, an LC4 640 Enduro and a 625 Supermoto, both street legal. I am interested in the Husabergs and am trying to learn about them but I need some help. What does the pre-fix FS and FE and the suf-fix c, e etc. mean? I saw an FS 650c in an online photo and it looks like the S...