I'm also interested in this topic. I previously posted a thread on
Swift spring conversion for V3s. My reason is I'd like to tighten up the rear a bit, but also prevent the coils from rubbing and groaning under full compression.
If the springs are going to be chatty as crfine mentions, then it might not be a good solution.
I've thought about just changing the rear shocks as well, but there doesn't seem to be anything that isn't either very loud or very expensive like
mcs. I don't know about the clubsports, but the V3s have reservoirs that make replacing the rear brake pads a bit of a chore (you can disconnect from the top mount if you have one, but it would be nice to not have to).