I have modded the numbers of turns in Simulation discriptor victory xml. I xhange the last  turn from Base value 299 to 9999 however it dosent show the new number of turns in the game speed mode and only shows the defaults. So even it shows the defaults does my changing of the number turns overide this and still work?

Some of the localizations strings are fixed, so yes, they will probably state the old values. It should work, but youll have to try that yourself ofcourse ;)