I know a good many folks that change recoil springs, typically to lighter ones, although some go heavier. As SilentHitz mentioned, sometimes people go lighter for lighter loads to make the gun work reliably, but some folks use them with "major" loads too.
When I competed with a Glock, I went heavier first and thought at first that they gun felt "flatter" in recoil. I liked it for a bit, but later realized the gun was actually dipping some when it went back into battery and it didn't feel like it tracked as consistently. I later went lighter than stock and ended up liking it better. I apologize for not knowing the weight, but it has been a while. 13lb seems familiar though.
Either way, heavier or lighter, it definitely changes the way the gun feels and tracks in recoil. I run lighter springs in my .40 Limited guns too for the same reason. I am currently running a 12.5lb. ISMI, but I have run as light as 11 in the past. I like the feel and the guns run just fine. Reliability is of course most important, and some guns will run with lighter springs than others.