I only used Gamecih in my attempts (it's a memory editing tool, requires root). Editing the value of the timer doesn't work. Changing the speed of the game works only partially. If it's a timed mission and I increase the speed, it is affected only the timer (the animations, the rates of fire stay the same). If I decrease the speed, the whole game is slowed down, not only the timer. Also, if it's a non-timed mission and I change the speed in any way, the whole game is affected.
Regarding the stats... I did a bit of research and it seems they're stored locally, not on the server. And even more, they're visible in Gamecih. I managed to edit my no. of ranking points, wins and losses (you get "General of the army" @ 4600 pts). But as I said, I'm not interested in this kind of hacks. This game has the worst matching system I ever saw (at least in my case), so I'm kinda "proud" of my 60+ defeats.