Does it make the sanwa stick perform like a ls-32?
If you want an ls-32, just get an ls-32 :P
It doesn't feel exactly the same with just a spring swap.
OK, next question...how does a seimitsu stick compared to a sanwa?
Not as floppy, little clickier. Personally I like the seimitsu more, but that might only because I'm very used to the ls-32.
It's really just personal preference, although I can completely understand that some people wouldn't care either way.
Right...now I see why its prefered for schmups...no room for floppies
the other thing is adding it inside the sanwa spring to make it a little stiffer...although you could just stretch the sanwa spring which is what I did for the same result...