If you are looking for side springs, you'll find a huge selection from different manufacturers. From Super Ultra Soft up too extra hard. But If you take a closer look, the differences aren't so big. So I made a short overview about the most common springs. The blue circle shows how I've counted. For the wire diametre I used calipers. So after that, it seems it's not such a miracle. If you habe some other intresting side springs, just give me some information about it and I'll add them to the list.
Anyway side springs are quiet important. So you should replace them after a while. Check if they are not bend and so on.