Yeah, you're joystick will definitely wear in over time with the original spring. It takes a while to get the metal used to moving and stretching so much, so just play really hard for a night, and feel it the next day, you'll probably notice it loosening up a little. I had this problem with my super joysticks at first, but I've played so aggressively on them that they're nice and loose now. My suggestion for extremely aggressive use of your joysticks: Marvel vs Capcom 2 for dreamcast, or even the first one on Cps2. If you're really worried about the spring, you might be able to talk to Bob Roberts over at
www.therealbobroberts.com and see if he can sell you another spring that fits the joystick better.
-Good Luck