Depends on your riding style I guess. When I was discussing the front fork set up with the guys at Dan Kyle they were asking what type of riding I did most. Was I cruising around, you know ride down to Starbucks and hang out for a while and then cruise back home? Or was I pushing it hard and riding like I stole it? If it was just cruising then they recommended the linear spring. If I was racing then they recommended the progressive spring. I had to tell them I would cruise to Starbucks and hang out for a while but then go out & ride it as hard as I could sometimes.
We settled on the progressive springs for the front. Never had that type of conversation regarding the rear spring. I like them just fine. Ben never liked progressive springing in the mountain bikes he rode but this might be another element and he never had any complaint about the front end of the 848, at least not that he expressed to me. Emile didn't have any negative comment either but he also liked the front of the 1198 just fine too and I don't think that bike is equipped with progressive springs but then I really don't know 100% for sure one way or the other on that part.
I didn't see Streetfighter options listed on their website.
The only real reason to change anything though is if there is a real problem or a hindrance to the way the bike is responding.
We could and should do the nylock tie strap test to the front forks and see just how much travel is occurring while you ride. That would tell us more about how well it is set for you.
