I loved. The best plugin you have ever made. Well done.
Something that if, as notedo3 said, it is strange to feel when you change the speed in different weapons or items, but if you want to change the walk for running as if it were in modern first person shooter.
Something that I would like to add (if possible) is that when your health is very low depending on the command "survivor_limp_health 40", which would be 39 and below. Your speed slows down, and instead doesn't change. Over there if you can Silvers, to add some command that allows you to change the speed to change when your health is very low, it depends on the value that you put according to the "survivor_limp_health" command.
Type like this:
"run" = "220.0"
"walk" = "85.0"
"crouch" = "75.0"
"hurt" = "150.0"
The "hurt" works when your health is at 39 and below, it depends as I said before the command "survivor_limp_health" which by default is at 40. Then your speed changes depending on your health.
I hope I have not complicated what I said and I do not know if I was able to express my answer well. Anyway, thanks for this great plugin!