The JLFs are smaller and have a much, much lighter spring. I don't think how light the spring is can be expressed. You just have to experience it.
Take the spring out of a pen, hold it at the bottom, and push it over at the top. It's kinda like that.

I'm pretty sure you wouldn't be happy with them using the original springs.
IMO, the 6lb springs that paradise sells make it feel like a beat 'em up stick, but you may want to order a set of the 4lb springs too in case the 6lb ones are too heavy for you.
Personally, I wouldn't fork over the money for 4 JLFs for a beat 'em up cab.
The ball tops will work on cheaper sticks like the zippy.
http://www.paradisearcadeshop.com/316-imported-joysticksI haven't used those though, so can't comment on the feel.