Good luck with the fps unlock. I currently have the com_maxfps to make one but changing its value will cause the game to crash. There is something that checks many dvars for any changes. If the value changes even by 1 and not by the game, it crashes.
You could try to simply jump over this function, didnt try it myself but probably that would work Because then the game just ignores the dvar and doesnt patch it^^
"VB is like that dumb chick that wants to have rights but would not even know how to handle them" - A smart guy